A teacher's________to the cause of education is worth great respect of the whole society because it brings countless benefits to the development of society.
He made a promise____he would achieve the success that his parents were looking forward to.
After a knock at the door, the children heard his mother’s voice him.
If we canour present difficulties, then everything should be all right?
We all know that, , the situation will get worse.
When the teacher speaks, we have to keep quiet, ?