Ответ:

1) Unless Tom
gives his library book back, he (will have) to pay a fine.

2) If the earth
suddenly (stopped) spinning, we all would fly off it.

3) If I knew that
dogs were allowed in the hotel, I (would bring) my dog.

4) If I had known
your problems with money I (would have lent) you some.

5) If you finished,we
(would go) for a walk.

6) The ice (will shatter)
if you walk on it, it’s too thin.

7) If I (had) a
university degree I wouldn’t be sitting in this office.