蒋健棠英语实用句子(125):He had to drop out of the race
He had to drop out of the race because his leg was injured.
因为他的脚受伤了，他不得不退出比赛。
drop out 有退出和退学的意思。
He dropped out of school when he was fifteen.
他15岁时退学了。
如果drop out连成一个单词，写成dropout或drop-out，就变成一个名词，意思是退学生。
His mother doesn't want him to be friends with those dropouts.
他的妈妈不想他和那些退学生交朋友。
