[单项选择]Many scientists are so convinced of the benefits of challenging the brain that they are putting it into practice in their lives（）
A. 许多科学家都确信，在他们的生活中，经常练习挑战大脑，就会带来效益。
B. 许多科学家都对勤于动脑的益处确信不移，他们在自己的生活中也努力实践着。
C. 许多科学家都如此确信挑战大脑会带来利益，他们的实际生活证实了这一点。
D. 许多科学家都相信，他们生命中所实践的就是对人的大脑挑战，这种挑战是有益的。

[单项选择]

Many scientists today are convinced that life exists elsewhere in the universe—life probably much like that on our own planet. They reason in the following way.
As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.
Life requires the right amount and kind of atmosphere. This eliminates all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere, a larger one would hold too much of it.
Life also required a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady
A. has different laws
B. has one common law
C. shares the same laws
D. shares no common law

[单项选择]

W: What shall I do I’ve got so many things on my mind now. Will anybody help me
M: Don’t ask me. It’s your baby, Mary.

What does the man mean by that（　）.
A. She is too busy.
B. He is willing to help.
C. It’s your problem.

[单项选择]An American scientist has found that many images of dinosaurs may be wrong. For years, pictures of the ancient creatures have shown their nose openings near the top of the head. The new study suggests the dinosaurs’ nostrils were just above the mouth.
Dinosaurs used their nostrils to breathe, smell and control their body temperature. The new theory could help explain how the huge creatures were able to survive by using their sense of smell to find food, a mate and possible enemies.
Lawrence Witmer of Ohio University in Athens, Ohio led the study. The publication science reported his findings.
Many of the early dinosaur remains recovered by scientists were from huge creatures called sauropods. Scientists believed that sauropods must have lived in water because their bodies were so huge and their necks were so long.
Nostrils high on the head would have permitted the dinosaurs to breathe while partly under water. The discovery of a sauropod head bone in 1884 added supp
A. They are close relatives to dinosaurs.
B. Their soft tissues survive as fossil remains.
C. Their soft tissues have similar traits with dinosaurs.
D. He cannot find living dinosaurs.