Where can ozone be found useful to life according to the passage？
A. Between ten and fifty kilometers up in the atmosphere.
B. In the far sky.
C. Near the sun.
D. Far from the sun.
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The most useful features of the course is______.
A. it enables trainees to deal with those demands or deadlines that they regard as unreasonable
B. it helps people realize stress is not always harmful
C. it helps people work more efficiently
D. it lets people know the relationship between work and stress
What can NOT be caused by a decrease or an increase in ozone？
A. Skin cancer.
B. Harm crops.
C. Harm animals and fish.
D. Increase in temperature.
"Prioritize" in the third paragraph means______.
A. arrange in order
B. give attention to
C. concentrate on
D. regard as
Which of the following can best summarize the passage？
A. The Nile is the source of flood.
B. The Nile is a highway for the people in Egypt.
C. The flat bottomed boats have been used.
D. The Nile made Egypt's civilization possible.
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