If we don’t study hard, we will _______ in our class.

David is a ______ musician. He can play the piano very ______ .

I’ll buy you a new watch if you learn to swim this summer.— Is there a ________ I’m sure I’ll get it.

Pollution has reached ______ high levels in some urban areas, which is quite worrying [ ]

下列各句中，没有语病的一句是