if john wants to get a good mark, he ____ study h

if john wants to get a good mark, he ____ study h

must/should/will

must

必须

如果约翰想取得好成绩，他就要学习

If john wants to get a good mark, he needs to study hard.
如果约翰想取得一个好成绩，他需要努力学习。
1. need to 作情态动词，通常用于疑问句、否定句、条件句、 whether(if) 名词从句或含否定意义的句子中。如：
I do not see why we need discuss it further.
我看我们没有必要讨论下去了。
That's all settled. It needn't be talked about.
那已全部解决了，没有必要再说了。
He asked me whether he need attend the meeting?
他问我他是否有必要出席这次会议？

2. need 又是实义动词，各种变化和用法与普通实义动词相同。如：
They need a rest after a long walk.
长距离行走后他们需要休息一下。
I need you to work for me, young man!
小伙子，我需要你为工作。