非谓语动词的恰当形式填空：

The ________(worry)mother looked at her ________(worry)son, looking ________(worry)．

非谓语动词的恰当形式填空：

These seats are ________(reserve)for you．

非谓语动词的恰当形式填空：

Some of the people ________(invite)to the party couldn’t come．

非谓语动词的恰当形式填空：

The experience ________(gain)will be of great value to us．

非谓语动词的恰当形式填空：

Don’t drink the ________(pollute)water．