问题补充：
I saw him, his humor impressed me.
A. The first time
B. At first
C. It was the first time
D. For the first time
答案：
(答案→)A. The first time
B. At first
C. It was the first time
D. For the first time
解析：考查连词。选择项中the first time第一次，为连词短语。B、C、D选择项不可以接从句。句意：当我第一次看到他，他的幽默给予我很深的印象。故A正确。
