问题补充:
Children are having a good time in the park.
A. have fun
B. enjoy themselves
C. having fun
D. playing games
答案:
A. have fun
B. enjoy themselves
(答案→)C. having fun
D. playing games
解析:句意:孩子们在公园玩的很愉快。having a good time意为“玩的开心”enjoy themselves , having fun 都有玩的开心的意思,但是句中有are,要用现在进行时的形式,故选C