At the party John made up a joke people burst out laughing.A. on whichB. by whichC. at wh

问题补充：

At the party，John made up a joke， people burst out laughing.

A. on which

B. by which

C. at which

D. from which

答案：

A. on which

B. by which

C. at which

D. from which

解析：“laugh at”固定搭配。