People are puzzled they read the book. A. the first timeB. at the first timeC. for the fi

问题补充：

People are puzzled they read the book.

A. the first time

B. at the first time

C. for the first time

D. at first

答案：

(答案→)A. the first time

B. at the first time

C. for the first time

D. at first

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