[填空题]The reason why people in the past believed that the ordinary Mayan people lived in the countryside was that their knowledge was based on uncovered large buildings.

[填空题]The reason why people in the past believed that the ordinary Mayan people lived in the countryside was that their knowledge was based on______.

[填空题]Many people wonder why some men want to live on the moon. It is (1) not the kind of place where most men would choose to live. But man has always moved to new areas.
Some scientists hope that continued work will be done on the moon. Many experiments will be done there more (2) . Some large (3) are very easy to do in a place without air. Matter can be heated to very high temperatures without (4) change when it is in such a place. Air, dust, and clouds cannot (5) man’s view of space from the moon. The very high or very low temperatures and low gravity on the moon will be used for many experiments. One very important use of the moon will be to (6) spaceship.
Man might be able to learn much about his own body by living on the moon. He would be living in a habitat that he made for himself. Man would be in control of the (7) of life in which he lives. (8) could be removed from the air in this

[填空题]

Why do people sometimes act differently towards the same event

[填空题]Why are the past-oriented people flexible in their early years

[填空题]Private claims advocates help people figure out their bills free of charge.

[单项选择]

Regeneration of Limbs
Most people would agree that it would be wonderful if humans could regenerate limbs. These who have lost their arms or legs would be complete again. The day is still far off when this might happen. But in the last 10 years, doctors have reported regeneration in smaller parts of the body, most often fingers.
Regeneration is not a newly-discovered process. For centuries, scientists have seen it work in some kinds of animals. Break off a lizard’s (蜥蜴的) tail, for example, and it will grow a new tail. Scientists now are looking for a way to turn on this exciting ability in more highly-developed animals, including humans. Their experiments show that nerves, cell chemistry and the natural electric currents in the body all seem to have a part in this process.
The body of every animal contains general purpose cells that change into whatever kind of cells the body needs. Animals such as the lizard or salamander (蝾螈) use these cells
A. general purpose cells.
B. bone cells.
C. muscle cells.
D. skin cells.