下列各句中，没有语病的一句是(　 　)

It is these poisonous products _____can cause the symptoms of the flu, such as headache and aching muscles. [ ]

_____ prepare for the coming exam, Dave stays up late every night.

下列各项中，加点的词语使用恰当的一项是（ ）

How about a game of chess— ____