The audience when they heard the humorous story.A. burst into laughing B. burst out laugh

问题补充：

The audience when they heard the humorous story.

A. burst into laughing

B. burst out laughter

C. burst into laughter

D. burst in laughing

答案：

A. burst into laughing

B. burst out laughter

(答案→)C. burst into laughter

D. burst in laughing

解析：考查短语：突然大笑起来burst into laughter = burst out laughing，句意：当他们听到这个幽默的故事观众们突然大笑起来。所以选C。