(2013·重庆模拟)—When did your brother begin to show his interest in medicine? —It was a Saturday he noticed his classmate experimenting on a frog in the lab.
It is on September 1ststudents go back to school every year.
The boy was excited he went to Beijing.
In fact, there is _____ thing as a free lunch in the world.
This is the office _____ my parents are visiting now.
Everybody got ____ when they heard the ____ story.