thenumberofstudents后应该＋are还是isthenumberof...的主语是复数还是单数啊?那么anumberof和anamountof还有amountsof

　　thenumberofstudents后应该＋are还是is

　　thenumberof...的主语是复数还是单数啊?

　　那么anumberof和anamountof还有amountsof