________ little children can onlydo________ little work.

下列各句中，加点的成语使用正确的一项是

Tom ______ with his grandmother for eight years，but now he is living by himself

We can’tagainst other countries in trade if we don’t develop our national economy(经济).

. It is only when we cannot see clearly_____ we come to see ______ important our eyes are.