what if用法有一道题是这样的：What if you-------yourself in the laborato

what if ...
如果...,会怎样?
if 是用来假设一个状况:If[状况],then[后果].
状况子句要用过去式(did),后果子句用过去未来式(would do).
举例
问:What if you cloned yourself in the laboratory?
答:Then I would play chess games with my clone.
could 是can的过去式,所以用在状况子句.
would 是用在后果子句.
举例
问:What if you could combine a cow and a tiger?
答:Then there would be a new animal specie.
What if 是等于 what would happen if :)