What does the passage mainly discuss
A. The equipment divers use.
B. The effects of pressure on gases in the human body.
C. How to prepare for a deep dive.
D. The symptoms of nitrogen bubbles in the bloodstream.
According to the passage, early-twentieth-century education reformers believed that ______.
A. different groups needed different kinds of education
B. special programs Should be set up in frontier communities to modernize them
C. corporations and other organizations damaged educational progress
D. more women should be involved in education and industry
この じしょは たいへん （ ）です。
A. いい
B. みじかい
C. さむい
D. ひくい
The phrase "coincided with" in the first sentence of Para. 2 is closest in meaning to ______.
A. was influenced by
B. happened at the same time as
C. began to grow rapidly
D. ensured the success of
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