depend on,depends on,放在句首用哪个?

问题描述:

depend on,depends on,放在句首用哪个?
depend on 放在句首应该加 s 如 “Depends on you”
还有类似的 Seems like ,放在句首应该加s 如 “Seems like she's so happy”

这个句式实际上省略了主语It,it指代所谈的事情
It seems like she's so happy
It depends on you
所以要加s