改正英语句子 下列句子各有一处错误,指出并改正

改正英语句子 下列句子各有一处错误,指出并改正
1.A crocodile has sharp tooth and hard skin.
2.the windows is clean.the door is clean also.
3.we must keep the classroom cleanly.
4.i can't look for my pencil case.
5.they likes apple,but not bananas.
6.what is your favourite hobbie?