Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Ex Input:
Context: It is unanimously accepted that there is an unmet need for pain medications that are both effective and safe. Unfortunately, no really novel analgesics have been approved over the past three decades. In view of both experimental and clinical evidence of a major role for nerve growth factor (NGF) in the generation and maintenance of a wide range of pain states, drug discovery efforts focusing on the development of anti-NGF agents have aroused particular interest. Several humanized anti-NGF monoclonal antibodies (mAbs) have entered clinical trials as potential analgesics. In this respect, tanezumab is at an advanced stage of clinical development while fulranumab, fasinumab and ABT-110, previously known as PG110, are in early phases of clinical development. This Current Opinion article aims at describing the rationale for targeting NGF for pain, reviewing the analgesic efficacy and safety of anti-NGF agents based on data from fully published studies, conference abstracts, and the US Food and Drug Administration (FDA) website, and discussing the possible future of these agents in managing chronic pain. Anti-NGF mAbs produced significant pain relief and functional improvement in patients with osteoarthritis of the knee and/or hip. Conversely, studies in non-specific lower back pain generated mixed results; overall, this condition appeared to be less responsive to anti-NGF agents than osteoarthritis. Finally, there was no conclusive evidence of the effectiveness of anti-NGF mAbs in some types of chronic visceral or neuropathic pain. Furthermore, these studies raised safety concerns about anti-NGF mAbs. As a class, these drugs may cause or worsen peripheral neuropathies. But the most problematic issue-which prompted the FDA to place studies of these compounds on clinical hold in 2010-was rapid joint destruction leading to joint replacement surgery. The aetiologies of these side effects have been much debated and their pathophysiology is poorly understood. After an Arthritis Advisory Committee meeting held in March 2012, pharmaceutical companies negotiated with the FDA on the conditions for restarting clinical studies. Although the FDA lifted its clinical hold, there remain many unresolved issues about the long-term efficacy and safety of anti-NGF mAbs. While acknowledging that the future of these drugs is unforeseeable, it appears that they may not be the safe and effective painkillers that have been awaited for decades. 
 Question: What is the target of tanezumab?

Ex Output:
ngf


Ex Input:
Context: Clay gets up from his trailer at the beach and drives to Mr. Jimmy's lush house, where he mows the lawn.Mr. Jimmy has a visit from David, who is concerned about his health. He then goes out to chat with Clay, his new gardener, and invites him to swim in the pool after he is done working. Clay says he needs to do another lawn later.An academic named Edmund Kay comes to visit Mr. Jimmy, and expresses his deep enthusiasm for his films. Jimmy takes him out back to the pool, and recalls his youth in London, and then his movement into movies and on to Hollywood.Mr. Jimmy becomes bored with Kay's questions, and suggests that Kay begin removing clothing in exchange for his answers. Kay begins disrobing to each of Jimmy's tales about homosexuals in Hollywood and making Frankenstein.Jimmy then gets lightheaded and needs Kay's help to get inside and lie down. His maid Hanna scolds him for chasing boys after just returning from the hospital.Jimmy goes to a doctor who explains that he had a stroke which has left his brain somewhat impaired.Jimmy sees Clay working out in the garden and invites him to talk over iced tea in his painting studio. Jimmy tells him he directed the first two Frankenstein movies, and they talk about his paintings. Jimmy tells Clay he has an expressive head and asks him to model for pay; Clay agrees.Clay arrives at Jimmy's house and Hanna asks if he is going to hurt him. Clay is confused, and she withdraws the question. Clay sits down in the studio to model for Jimmy, who asks him to remove his shirt, even though he only plans to draw his face. Jimmy begins to draw, telling Clay of a memory he has about eating fat drippings as a poor child. He explains how different he was from his family, more talented, more intelligent.Clay goes to a bar and boasts that a famous director is drawing him. Betty the bartender, whom Clay has slept with, turns on The Bride of Frankenstein on TV; meanwhile, Jimmy watches at home with Hanna. The others at the bar criticize the film for not being scary. Clay seems to understand the monster's feelings of loneliness.Flashback: Jimmy directs the performers on the set of Bride of Frankenstein.Clay and Betty talk outside the bar, and he gets upset that she does not want to sleep with him again.Clay calls his parents from a payphone but does not want to talk much.Jimmy dreams that Clay is Dr. Frankenstein, replacing his brain and electrifying him.Hanna tells Clay that Jimmy would like him to have lunch. The two talk as she cooks, and Hanna tells him he should be married. Hanna tells Clay that Jimmy commits unspeakable sins of the flesh, buggery. She is surprised that Clay did not know.Jimmy and Clay have a rather fancy lunch. Jimmy tells Clay that he had hoped Bride of Frankenstein would be seen as a comedy. Jimmy asks Clay to pose for an hour after lunch, and he declines. Jimmy explains that he had a "husband" named David, and Clay asks about his homosexuality. They smoke cigars, and Clay agrees to pose.During the sitting, Jimmy talks about how he made the successful Show Boat and then tried to make his WWI masterpiece The Road Back but the studio butchered it. He says he always wanted to go back to movies, but that was the end. He also broke up with David thereafter. Jimmy begins to describe how he used to have many male models, all naked, which upsets Clay so much he gets mad and storms out.Clay goes to Betty's bar but she is not there. He finds another woman and has sex with her in the parking lot.Clay returns to Jimmy's house and says he will sit for him again if he eases up on the locker room talk. Jimmy is curious that Clay has never known any gay men before, not even when he was in the Marines. Jimmy recalls a young soldier from WWI he mentored in the trenches, then becomes quite upset, looking at Clay intensely 
 Question: Who is befriend with handsome gardener and former Marine?

Ex Output:
jimmy


Ex Input:
Context: Groups 13-16 of the periodic table (orange in the Figure 1.1) are the only groups that contain elements classified as metalloids. Unlike other groups of the periodic table, which contain elements in just one class, groups 13-16 contain elements in at least two different classes. In addition to metalloids, they also contain metals, nonmetals, or both. Groups 13-16 fall between the transition metals (in groups 3-12) and the nonmetals called halogens (in group 17). Metalloids are the smallest class of elements, containing just six members: boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te). Metalloids have some properties of metals (elements that can conduct electricity) and some properties of nonmetals (elements that cannot conduct electricity). For example, most metalloids can conduct electricity, but not as well as metals. Metalloids also tend to be shiny like metals, but brittle like nonmetals. Chemically, metalloids may behave like metals or nonmetals, depending on their number of valence electrons. Q: Why does the chemical behavior of an element depend on its number of valence electrons? A: Valence electrons are the electrons in an atoms outer energy level that may be involved in chemical reactions with other atoms. Group 13 of the periodic table is also called the boron group because boron (B) is the first element at the top of the group (see Figure 1.2). Boron is also the only metalloid in this group. The other four elements in the groupaluminum (Al), gallium (Ga), indium (In), and thallium (Tl)are all metals. Group 13 elements have three valence electrons and are fairly reactive. All of them are solids at room temperature. Group 14 of the periodic table is headed by the nonmetal carbon (C), so this group is also called the carbon group. Carbon is followed by silicon (Si) and germanium (Ge) (Figure 1.3), which are metalloids, and then by tin (Sn) and lead (Pb), which are metals. Group 14 elements group have four valence electrons, so they generally arent very reactive. All of them are solids at room temperature. Group 15 of the periodic table is also called the nitrogen group. The first element in the group is the nonmetal nitrogen (N), followed by phosphorus (P), another nonmetal. Arsenic (As) (Figure 1.4) and antimony (Sb) are the metalloids in this group, and bismuth (Bi) is a metal. All group 15 elements have five valence electrons, but they Germanium is a brittle, shiny, silvery- white metalloid. Along with silicon, it is used to make the tiny electric cir- cuits on computer chips. It is also used to make fiber optic cableslike the one pictured herethat carry telephone and other communication signals. vary in their reactivity. Nitrogen, for example, is not very reactive at all, whereas phosphorus is very reactive and found naturally only in combination with other substances. All group 15 elements are solids, except for nitrogen, which is a gas. Group 16 of the periodic table is also called the oxygen group. The first three elementsoxygen (O), sulfur (S), and selenium (Se)are nonmetals. They are followed by tellurium (Te) (Figure 1.5), a metalloid, and polonium (Po), a metal. All group 16 elements have six valence electrons and are very reactive. Oxygen is a gas at room temperature, and the other elements in the group are solids. Q: With six valence electrons, group 16 elements need to attract two electrons from another element to have a stable electron arrangement of eight valence electrons. Which group of elements in the periodic table do you think might The most common form of the metalloid arsenic is gray and shiny. Arsenic is extremely toxic, so it is used as rat poison. Surprisingly, we need it (in tiny amounts) for normal growth and a healthy nervous system. form compounds with elements in group 
 Question: metalloids include the element

Ex Output:

germanium.