Hearing their grandpa was coming, they began to ________ the work to prepare for a nice dinner.

Who is the person talking with you just now? — Well, if you ______ know, his name is David.

In the city the old ______.

What’s the matter with you? — After the long walk, my legs _______ and I couldn’t even take one more step.

下列各句中，没有语病的一句是（）