1.Serve for the people is our duty.前面应该用名词
2.It is easy to do it by yourself.be动词后面用形容词
3.If you late 30 minutes ,your friends will may get angry.不知道怎么说
4.Because I didn't ask anyone,I took the wrong book.
Because和so不可以连用
还有上楼的那个连谢谢都打错了,哥哥来教你,是thank you
还可以变形哦~thanks连这都不会~哼