Students are encouraged to the design petition for robots at the university.
A. take part
B. operate
C. join to
D. participate in
网友回答
A. take part
B. operate
C. join to
(答案→)D. participate in
解析：本题考查动词辨义。participate in sth 意为“参加（某项活动）”。take part后应加in。