American students take part in a wide variety of after-school activities _______ they develop their social skills.
As is known, it was Hu Jintao, _______ president of our nation, who gave ________ lecture at the ceremony of National Day
---Excuse me, Dad, but I am going to the club to meet my friends in the football team.---OK.
The Green Corporation donated the property to the state of California, with one condition ____ the Green family would be allowed to use it when they wished.
If Rose ____ her diamond in a safer place, it ____ stolen.
The plan ________encourage the employees to improve their work turned out to be a success.