Question

这个英语句子的句法和结构是什么呀？

Making the jump from the biology of what we know of melatonin to th the effect it's having on sleep is completely flawed。其中的the effect it's having on sleep ，it's 是什么用法?

Answer 1

it's having on sleep为定语从句，修饰the effect，定语从句用了现在进行时。

追问

那不应该是the effect that is having on sleep吗？

Answer 2

(Making the jump from the biology of what we know of melatonin to th the effect it's having on sleep 主句的主语) is completely flawed 谓语

Making the jump 动名词+宾语

from （the biology of what we know of melatonin 介词宾语） to （the effect it's having on sleep 介词宾语）
what we know of melatonin 宾语从句，做介词 of 的宾语

it's having on sleep 定语从句，修饰 the effect

追问

那不应该是the effect that is having on sleep吗？

追答

the effect it's having (the effect) on sleep
effect 在从句里是宾语，所以省略的连接词。