the reason , research shows that laughter is good for your health.
A. Whatever
B. Whenever
C. Whichever
D. However
网友回答
(答案→)A. Whatever
B. Whenever
C. Whichever
D. However
解析：
根据句意：研究人员发现，不管什么原因，笑都有利于你的健康。
Whatever无论什么 whenever无论何时 whichever无论哪一个 however无论怎样
故选A