Question

He stepped into the office, ________ down and began to fill in the forms.

1. A.
   sitting
2. B.
   to sit
3. C.
   sat
4. D.
   having it

Answer 1

C
该句意为“他走进办公室，坐下来后开始填表”。根据前面的stepped into the office和后面的began to fill in the forms这两个动作能够推断出，sat与它们是一个主语发出的三个并列动作，故形式应一致，也用一般过去式。