It’sno use ______ without taking action.

For some time the expert __________ people of the health risks caused by passive smoking. He says he won’t stop until all the smokers around him decide to quit smoking.

下列各句中，没有语病的一句是（3分）

________ it comes to the increasing use ofmotor vehicles in the cities，some people think it should be limited

You are quite free now, I think—_______, I have tons of things to do[ ]