When he heard the sad news, he _____ completely.
A. broke away
B. broke up
C. broke down
D. broke out
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If you want to telephone him, you will have to _____ the number in this book.
A. look up
B. look through
C. look into
D. look at
依据课程,推销自己的产品要对()有十分明确的认识。