下列各句中，没有语病的一句是（ ）

The experiment shows that proper amounts of exercise ,if _______regularly, can improve our health.

( )28.－_____ you put away your books－Yes,mum. I’ll do it at once.

Children, who grow up in a friendly family,are more ______ to get along wellwith others.

In ,the northerners are keen on dumplings while the southerners are fond of rice.