Black holes can not be seen directly, so determining the number of them is a____

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Black holes can not be seen directly, so determining the number of them is a___________ task.   [     ]
A. rough
B. strict
C. tough
D. firm

答案

举一反三

Compared with his sister, Jerry is even more___________ to, and more easily troubled by, emotional
and relationship problems. [ ]

A. sceptical
B. addicted
C. available
D. sensitive

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After months of overworking, she was suffering from __________and physical exhaustion.   [     ]
A. mental
B. medical
C. fatal
D. psychological

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In those days, our _____ concern was to provide people who were stopped by the snow storm with
food and health care. [     ]
A. normal
B. constant
C. permanent
D. primary

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A lot of small companies have to fight for _____ in such economic climate.   [     ]
A. survival
B. survivor
C. survive
D. exist

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When the shy girl couldn"t answer the teacher"s questions, she felt _____ and uncomfortable.    [     ]
A. tough
B. awkward
C. sceptical
D. curious

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