题目内容
单句改锗
下句中都有一处错误，指出并改正。
It is vainly to try to save him. ________
改vainly为vain
It is known to all, she is always ready to help others. ________
Come out from back the door. ________
The article is very important as short. ________
He had been to there before the war. ________
