有一个很简单的句子,I think he needs our helps .(改成否定句)I don't think h

有一个很简单的句子,
I think he needs our helps .(改成否定句)
I don't think he needs our help.
need干吗要加s啊?牵涉到什么 语法了?
我觉得：facaishuayachengnan830108
的回答还不完整．三单结构我早掌握了，只是想更深层的去知道知识呢！好象什么从句有个”主将从现”的结构的，和这个有联系吗＞我搞混了，我在现实生活中的老师不是个老师，不会讲授的．只好到网上了，我真的学的很苦啊．英语98％都是自学的！希望大家可以晌个脸讲一下．