问题补充：
Betty shows great interest in this poem now, but she thought it boringshe read it.
A. at the first time
B. the first time
C. for the first time
D. at first
答案：
A. at the first time
(答案→)B. the first time
C. for the first time
D. at first
解析：the first time名词词组作连词，连接句子。
