27: 1 ask, don't ask 2 questions, don't ask 3 answers, one is 6 and the other is the root sign. Anyway, find it by formula.

28: 1 q, forget it, 2 q is a rectangle (a square is absolutely wrong! ) 3 q: 1, q: 3, q

Multiple choice questions are basically simple. I remember the last question seems to be B, I can't remember clearly, that is 1**4. 1**5-!

The last question in the blank is 6, and everything else is very simple.