强调句能不能强调状语从句？

如It is because he does not come to the meeting that makes the boss angry.正确吗

当然可以的，强调句可以强调除谓语，补语以外的任何其他句子成分。
It was yesterday that I came acorss him on the street.

可以。

这句话是正确的。 强调句句型为it is+强调部分+that（who，which），被强调部分可以是主语，宾语，状语，但不能是谓语。