teacher是可数名词吗?

　　Gwendolen started fighting her teachers.

　　格温德琳开始和她的老师们争吵。

　　His teachers seem to have given up on him.

　　他的老师似乎不再对他抱有希望。

　　I wouldn't have dared to defy my teachers.

　　我可不敢不听老师的话。

　　Children often try it on with new teachers.

　　儿童经常设法戏弄新来的老师。

　　I'd put them both down as retired teachers.

　　我看他们俩都是退休教师。