填空题 There are twelve people take part in the experiment, four working as a group.
A. There are
B. take part in
C. working
D. as a
【正确答案】
【答案解析】B 应改为taking part in。[解析] 应改为taking part in，分词短语做定语。本句的意思是：“有12个人参加了试验，4个人一组。”