[简答题]Excessive speed plays a major role in as much as one fifth of all fatal traffic accidents, according to the foundation.

[简答题]Excessive speed plays a major role in as much as one fifth of all fatal traffic accidents, according to the foundation.

[单项选择]

Sleep plays a major role in preparing the body for an alert and productive tomorrow. But sleep is not a period of inactivity. The sleeping brain is highly active at various times during the night, performing numerous "house keeping tasks". These keep us alive and aid our ability to think and remember. Sleep also energizes the body and brain. Most people spend one-third of their lives sleeping and this will affect the other two-thirds in terms of alertness, energy, moods, body weight, perception, memory, thinking, reaction time, productivity and performance.
To limit sleep means our health and daytime potential are significantly reduced. So, good sleep strategies are essential in order to feel energized day after day. There is no strategy which works for everyone, so each person needs to experiment. One important thing is that you shouldn’t worry too much if you go a few nights without a lot of sleep. It won’t ruin your life. On any given night, one i
A. it is a period of complete inactivity for the brain
B. it helps us understand what we have already achieved
C. it makes us more effective when we are awake
D. it helps us to lose weight

[填空题]Sugarless food, such as ______ ,plays a role in the prevention of tooth decay.

[单项选择]Playing a major role in the economic life of the United States, （）.
A. women currently make up 46 percent of the work force
B. currently women make up 46 percent of the work force
C. the work force is currently made up of 46 percent women
D. 46 percent of the work force is currently made up of women

[填空题]______play a major role in the development of cancer.

[单项选择]Ocean water plays an indispensable role in
supporting life. The great ocean basins hold about
300 million cubic miles of water. From this vast
Line amount, about 80,000 cubic miles of water are
(5) sucked into the atmosphere each year by evapora-
tion and returned by precipitation and drainage to
the ocean. More than 24,000 cubic miles of rain
descend annually upon the continents. This vast
amount is required to replenish the lakes and
(10) streams, springs and water tables on which all
flora and fauna are dependent. Thus, the hydro-
sphere permits organic existence.
The hydrosphere has strange characteristics
because water has properties unlike those of any
(15) other liquid. One anomaly is that water upon
freezing expands by about 9 percent, whereas
most liquids contract on cooling. For this reason,
ice floats on wat
A. comparison and contrast
B. juxtaposition of true and untrue ideas
C. general statements followed by examples
D. hypothesis and proof
E. (E) definition of key terms