Is this __________book?–No．That is ___________ book．

______ is a possibility______ Jim will get first place in the long jump.

Stressful environments lead to unhealthy behaviours such as poor eating habits which _______ increase the risk of heart disease.

I think the man over there must be Bob.—It ______ be him. He has gone to Paris.

Take your maths book, Jim. Don’t ______ it at home again.