问题补充：
Did they the English speaking competition?
A. join
B. joined in
C. take part in
D. make part in
答案：
A. join
B. joined in
(答案→)C. take part in
D. make part in
解析：根据did后面跟动词原形的用法，可将B排除；根据题干，本句的意思是“他们参加了英语演讲比赛吗？”“参加”是join和take part in。Join表示参加一种组织，take part in表示参加某项活动，competition是活动，故take part in。所以本题选C 。
