1.句型：Thereasonwhy……意为“……的原因”

Thereasonwhylaughtercanreducepain笑能够减少疼痛的原因

2.动词seem的用法：seemstobe意为“似乎是”

3.表语从句thatithelpsproduceendorphins（内啡肽）inthebrain

它（笑）能帮助产生大脑中的内啡肽

整合起来的句意就是：

笑能够减少疼痛的原因似乎是它能帮助产生大脑中的内啡肽.

答案看完了,就采纳一个呗!拜托啦!嘿嘿

百度答题人伤不起呀~%>_,3,Thereason/（whylaughtercanreducepain-是thereason的同位语）到这里为止可看成是主语/seemstobe(thatithelpstoproduceendorphinsinthebrain整块做seemtobe里的that从句.)-这是整个句子的谓语和宾语,2,主语thereason

谓语seemstobe

宾语从句that后面,1,句子主干的主语是Thereason，谓语seemstobe。

这个句子包含两个从句：

【Thereasonwhylaughtercanreducepain】这是一个定语从句，先行词是reason，why是关系副词，“笑能减轻疼痛的原因”.......

Thereasonwhylaughtercanreducepainseemstobe...,1,主语是“thereason”,whylaughtercanreducepain同位语从句，seemstobe应该是谓语，that是宾语，后面是宾语从句。,1,一个英语句子结构的分析---在线等---高手进

Othertestshaveshownthatlaughterappearstobecapableofreducingtheeffectofpainonthebody.Inoneexperimentdoctorsproducedpainingroupsofstudentswholistenedtodifferentradioprograms.Thegroup,whichtoleratedthepainforthelongesttime,wasthegroup,whichlistenedtoafunnyprogram.Thereasonwhylaughtercanreducepainseemstobethatithelpstoproduceendorphins（内啡肽）inthebrain.

分析这个句子结构：Thereasonwhylaughtercanreducepainseemstobethatithelpstoproduceendorphins（内啡肽）inthebrain.