Рассчитайте степень полимеризации изопренового каучука с молярной массой 13 600.

Present Perfect/  Past Simple. Use either the  Present Perfect or  Past Simple in the following sentences.                                                                                 a)Past Simple      b) Present Perfect 

1) George went to the cinema,but he_______ (not to enjoy) the film much.

2) ________you ever____(to have) any serious illness?

3) I____(tocome) to school without glasses. I can"t read the text.

4) Who_____(to eat) all the apples?

5)So far we____(to have) no troubles.

6) Jane____(to move) to a new flat a month ago.

7)We____(to wonder,often) where he gets his money.

8) do you know that they____(to be born) on the same day?

9) how often___you___(to fall) in love?

10)I"m delighted to tell you that you___ (to pass) your exam.

11) I____(to use) to swim every day when I was young.

12) I_____ (to break,already) two plates. Shall I go on washing up?

13) I"m not sure we___(to meet) before.