下列各句中，没有语病的一项是（ ）

In our school students are ________ according to how much they know and how old they are.

The government requires that every primary school student do sports for at least one hour every day.— _____. It is high time that students took exercise in order to build a strong body.

ows nothing about it, so he can’thelp _______ any of your work

Not until then _____ their marriage was breaking up because they had little in common.