问题补充:
They were busy an experiment when I came.
A. doing
B. to be doing
C. with doing
D. to do
答案:
(答案→)A. doing
B. to be doing
C. with doing
D. to do
解析:考查固定搭配。固定搭配:be busy doing sth忙于做某事;be busy with sth忙于某事;句意:当我来的时候,他们忙于做实验。故A正确。
时间:2018-10-01 20:40:23
They were busy an experiment when I came.
A. doing
B. to be doing
C. with doing
D. to do
(答案→)A. doing
B. to be doing
C. with doing
D. to do
解析:考查固定搭配。固定搭配:be busy doing sth忙于做某事;be busy with sth忙于某事;句意:当我来的时候,他们忙于做实验。故A正确。