Air pollution results in stronger greenhouse effect, which __________ leads to global warming. We must take measures to prevent pollution before it is too late.

The rescuing soldiers in the helicopters ______ to land on that earthquakestricken area, but failed again and again.[ ]

Carter was saying all the right things, but his smile was __________, and I knew I couldn’t trust him.

Sports and games should not be _____ only_____ amusements

Do you know if he________tomorrow