题目内容：

.Both ______ and ______ laughter do harm to your health.
A.burst into tears;burst into B.to burst into tear;to burst into
C.bursting into tears;bursting into D.tear;/

优质解答

选 C. bursting是burst的动名词形式,Both...and ...,中间接的都是名词或代词.Burst into tears突然大哭,burtt into laughter突然大笑.