Warm water freezes more quickly than cold water. Sir Francis Bacon said that almost four hundred years ago. But few people believed him until 1970. In that year a Canadian scientist George Kill proved the English professor was right. Dr Kill filled an open oil pail with cold water. He filled another with warm water. He put both in the same low temperature. The warm water froze first. The lack of covers on the pails is the secret. Some of the warm water changed into vapor. This meant that less of the warm water was left to be frozen. And so the warm water froze faster than the cold water even though it had a greater temperature drop to make. Hundreds of years ago, Sir Francis Bacon found _ . A) the temperature of warm water drops faster than that of cold water B) warm water is heavier than cold water C) warm water has the same temperature as cold water D) warm water is not as useful as cold water
A
Orcas, or killer whales, are the largest of the dolphins and one of the world's most powerful animals feeding on meat. They feast on marine mammals such as seals, sea lions, and even whales, employing teeth that can be four inches (ten centimeters) long. They are known to grab seals right off the ice. They also eat fish, squid , and seabirds. Though they often frequent cold, coastal waters, orcas can be found from the polar regions to the Equator . Killer whales hunt in deadly groups, family groups of up to 40 individuals. There appear to be both permanent and temporary group populations of killer whales. These different groups may hunt different animals and use different techniques to catch them. Permanent groups tend to prefer fish, while temporary groups target marine mammals. All groups use effective, cooperative hunting techniques that some are similar to the behavior of wolf packs. Whales make a wide variety of communicative sounds, and each group has various noises that its members will recognize even at a distance. They use echolocation to communicate and hunt, making sounds that travel underwater until they meet objects, then reflect back, showing their location, size, and shape. Killer whales are protective of their young, and other adolescent females often assist the mother in caring for them. Mothers give birth every three to ten years, after a 17-month pregnancy. Killer whales are immediately recognizable by their special black-and-white coloring and are the intelligent, trainable stars of many aquarium shows. Killer whales have never been widely hunted by humans. We can conclude that _ . A) people can find killer whales everywhere around the world B) killer whales live in different groups and never live alone C) by making sounds killer whales hunt and communicate D) humans' hunt has made killer whales being endangered
C
Q: In prefix = st1 /America, drivers' education is part of high school. Every student in his or her second year of high school is required to take a course in drivers' education. However, unlike other courses, it isn't given during the regular school year. Instead, it is a summer course. The course is divided into two parts: class time for learning the laws and regulations, and driving time for practice. The students study the basic traffic laws they must know to pass the written driving test, which is given to anyone who wants to get a driver's license. Driving time is a chance for the students to sit behind the steering wheel and practice all kinds of skills that are required to drive a car. Each student is required to drive for a total of six hours. The students are divided into groups of four. The students and the instructor go out driving for two hours. Thus, each student gets half an hour of driving time per outing. The instructor and the "driver" sit in the front seats and the other three students sit in the back. The cars for drivers' education are different from other ears. In this kind of car there are two sets of brakes, one on the driver's side and the other on the instructor; s side. Thus, if the student driver runs into difficulties, the instructor can take over. This kind of car also has another special feature. On the rear window of the car is a sign that reads: STUDENT DRIVER. That lets nearby drivers know that they should be more careful because the student driver isn't very experienced. After the student has passed the drivers' education course and reached the proper age to drive, they can go to a designated state office to take the driving test, which is made up of an eye examination, a written test, and a road test. The student must pass all the three tests in order to get a driver's license. If the student does well in the drivers' education class, he or she will have no problem passing the test with flying color1s and getting licensed. Which of the following does NOT agree with the requirements for the students wanting to get their driver's licenses? A) Their age must conform to relevant regulations. B) They should go to have their driver's tests. C) They must have their eyes examined. D) They can take the driving test in their own schools.
A: D
(Question)
I am peter Hodes ,a volunteer stem courier. Since March 2012, I've done 89 trips of those , 51 have been abroad, I have 42 hours to carry stem cells in my little box because I've got two ice packs and that's how long they last, in all, from the time the stem cells are harvested from a donor to the time they can be implanted in the patient, we've got 72 hours at most, So I am always conscious of time. & I had one trip last year where I was caught by a hurricane in America. I picked up the stem cells in Providence, Rhode Island, and was meant to fly to Washington then back to London. But when I arrived at the check-in desk at Providence, the lady on the desk said:"Well, I'm really sorry, I've got some bad news for you-there are no fights from Washington."So I took my box and put it on the desk and I said:"In this box are some stem cells that are urgently needed for a patient-please, please, you've got to get me back to the United Kingdom."She just dropped everything. She arranged for a flight on a small plance to be held for me.re-routed me through Newark and got me back to the UK even earlier than originally scheduled. For this courier job, you're consciously aware than that box you're got something that is potentially going to save somebody's life. Which flight did the woman put Peter on first? A) To London B) To Newark C) To Providence D) To Washington
(Answer)
B