主语从句问题

1)The team leader of mountain climbers marked out what seemed to be the best route.
此句话正确，What在句中既引导宾语从句，又在从句中作seemed的主语
是的。

2)The team leader of mountain climbers marked out something that to be the best route.
此句话正确还是错误？为什么？
错误，因为that后面引导的从句因该是个完整的句子，有主语谓语。所以to be 要改成is.

something that seemed to be 吧...如果和上句意思一样的话

The team leader of mountain climbers marked out something that to be the best route.这句话是错误的。因为something后面跟的从句是一个定语从句，所以动词要用谓语动词，不能用动词的to be形式。