The reason ______he is so upset is ________ his father is coming to school for the teacher-parent meeting today.
Mary and her friends paid_____visit to _______Summer Palace yesterday.
It was back home after the experiment.
is believed that improvement in health care will lead to a stronger , more prosperous economy .
----May I smoke here ? -----If you , choose a seat in the smoking section .
I like getting up very early in summer. The morning air is so good .