If you can open the box,I can close it.这一句是虚拟吗?

题目

If you can open the box,I can close it.这一句是虚拟吗?
If you can open the window,I can close it.这一句是虚拟吗?
但我看语法书上面,虚拟的主句要用will/shall...
现在越来越搞不明白了.

答案

这里不是虚拟,这里是强调事实.
如果是虚拟就是与现实相反,或者不存在的事情.
比如,
If I were a bird,I would fly in the sky