Langping, who is said to have started her coaching career in America,__volleyball in China for 20

Langping, who is said to have started her coaching career in America,__volleyball in China for 20

问题补充：

play不是应该发生在start之前吗

跟这个无关,
Langping played volleyball in China for 20
这只是说明一个事实.并没有产生影响,所以用过去时.
如果补一句,"这使得中国排球怎么怎么样了"——有了影响，才能用完成。

who is said to have started her coaching career in America

People say that she have started her coaching career in America,__

start 在say前面，对people的印象产生了影响，所以才有的完成时。

OK？

Langping played volleyball in China for 20

这是主语,用过去时,说明一个事实.

郎平在中国打排球20年.

who is said to have started her coaching career in America
据说在美国已开始了她的执教生涯.
因为对现在有影响,所以才用完成时,

played 是陈述一个过去发生的事实，已经结束了
had played 是持续的，表明从过去发生一直到现在为止
这句说郎平过去在中国打了20年排球，但尤其强调现在在美国执，所以必须用played儿不是had played

过去分词作修饰 表伴随