英语的句子成分大体上有以下：
1.主语：Tom is watching TV now.Tom就是主语.
2.谓语：They study English hard.stud是谓语.y
3.宾语：I play basketball every afternoon.play就是宾语.
4.定语：Mary bought a pen.pen是宾语.
5.状语：He is reading a book carefully in the room now.carefully方式状语,in the room地点状语,now时间状语.
6.表语：They are students.They 是主语,are是连系动词,students就是表语.
7.补语：
The boss told the workers to be careful.to be careful是宾语the workers的补语,叫宾语补足语,简称宾补.
The workers were made to work 12 hours a day.to work 12 hours a day是主语the workers 的补语,叫主语补足语,简称主补.