______his arrival at the classroom on his first day at school, the teacher _______[ ]

If you want to work out the problem of stress successfully, you need to find out the _________ first.

下列各句中文学常识的表述，正确的一项是（ ）

Your school things should _____.

______ your sister ______ in Greener China for a long time—Yes.She joined it five years ago.