In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Input: Consider Input: Passage: The two main requirements of an anti-torque system are that it should prevent rotation of the sonde, and it should allow easy movement of the drill up and down the borehole.  Attempts have been made to design drills with counter-rotating components so that overall torque is minimized, but these have had limited success.  Five kinds of anti-torque systems have been devised for use with cable-suspended EM drills, though not all are in current use, and some drills have used a combination of more than one design.  The first drill to require an anti-torque system was used at Camp Century by CRREL in 1966; the drill incorporated a set of hinged friction blades that swung out from the sonde when the drill motor was started.  These were found to have very weak friction against the borehole wall, and were ineffective; the drill had to be controlled carefully to prevent twisting the cable.  No other drills have attempted to use this approach.For the next deployment of the drill leaf springs were installed, and this has proved to be a more durable design.  These are mounted vertically, with a curve outwards so that they are easily compressed by the borehole wall, and can slide up and down with the movement of the drill.  They pass easily through any areas of irregularity in the borehole, but the edges of the springs cut into the borehole wall and prevent rotation.  Leaf springs are very simple mechanically, with the additional benefit of being easy to adjust by changing the spacing between the end points.  They can be placed anywhere on the drill that does not rotate, so they do not add length to the sonde.  The shape is usually a fourth-order parabola, since this has been determined to provide the most even loading against the borehole wall.  Leaf springs have been found to be so effective that they can prevent rotation even in heavy drills running at full power.Skate antitorque systems have blades attached to vertical bars which are pushed against the borehole wall; the blades dig into the wall and provide the anti-torque.  Skates can be built with springs which allow them to keep the blades pressed against the wall in an irregular borehole, and to prevent problems in narrower parts of the borehole.  Although skates are a popular design for anti-torque and have been used with success, they have difficulty preventing rotation in firn and at boundaries between layers of different densities, and can cause problems when drilling with high torque.  When they fail, they act as reamers, removing chips from the wall which can fall to the drillbit and interfere with drilling.

Output: What acts as reamers when they fail?


Input: Consider Input: Passage: In the years following the eruption, despite earning rapid fame and opportunities to research internationally in Japan, New Zealand, and Guadeloupe, Glicken still failed to obtain a job at USGS. Senior employees at the Survey found his behavioral oddities unsettling. Activity at Mount St. Helens diminished, prompting USGS to reduce CVO's budget and contemplate closing the station. He continued helping the Survey until 1989, also serving as an assistant researcher at the University of California at Santa Barbara.From 1989 to 1991, Glicken continued his volcanological studies in Japan as a postdoctoral fellow at the Earthquake Research Institute of the University of Tokyo, supported by grants from the U.S. National Science Foundation. Later, while a research professor and translator at Tokyo Metropolitan University, Glicken became involved with research at Mount Unzen. The volcano had recently resumed eruptive activity in November 1990, after being dormant for 198 years. In the months after its first activity, it erupted sporadically, and the government evacuated its vicinity near the end of May 1991. On June 2, 1991, Glicken visited the mountain with Katia and Maurice Krafft. The three entered a danger zone near the base of the volcano the following day, assuming that any potentially hazardous pyroclastic flows would follow a turn in the landscape and safely bypass them. Later that day, a lava dome collapsed, sending a large flow down the valley at 60 miles per hour (97 km/h). The current reached the turn before separating into two parts, and the upper, hotter part swiftly overcame the volcanologists' post, killing them upon impact. In total, 41 or 42 people died in the incident, including press members who had been watching the volcanologists. The volcano burned down 390 houses, and the remains of the flow extended 2.5 miles (4 km) in length. Glicken's remains were found four days later, and were cremated according to his parents' wishes. To date, Glicken and Johnston are the only American volcanologists known to have been killed by a volcanic eruption.

Output: What is the last name of the American volcanologist that has died along with the man continued his volcanological studies in Japan?


Input: Consider Input: Passage: Two men named Ty and Vachel are hunting in a forest and come across an abandoned church, which they go in to explore. After Ty sees their truck being crashed into a tree, Vachel is stabbed with a serrated machete by a chuckling assailant who then dons Vachel's hat and jacket. Ty, seeing the murderer come out of the church, quietly flees off into the forest. Meanwhile, forest ranger Roy McLean is at his home, where he encounters a van of five college-aged adults heading to rural property which one of them has inherited. Despite his insistence that they not venture up the mountain, the five continue along. Among them are Warren; his girlfriend Constance; Jonathan, and his girlfriend, Megan; and Daniel, Jonathan's brother.
On their way up the mountain, they hit a deer, and encounter Ty stumbling through the woods on his way down the mountain; they dismiss his warnings of "demons," as he is visibly drunk. After reaching a point where the van cannot drive any further, the group set out on foot and make a campsite; at night, while around the fire, Constance, Megan, and Daniel hear noises around them and become frightened, only to find that Jonathan and Warren are playing a joke on them. The next morning, they hike along Silver Creek to a waterfall, where they see a young girl named Merry Cat Logan singing before noticing their presence and running into the woods. Megan and Jonathan go skinny dipping at the bottom of the falls, unaware that someone else has entered the water. Megan feels hands touching her and assumes it's Jonathan, until she sees him on shore, whereupon she panics and swims to safety.


Output: Which college students frighten the other by making noises at the campsite?