We teenagers shouldn’t be impatient _____ our own problems. _____ they are solved, we can never give up.
–Do you still remember the city ____ we visited last year ?--You mean Zhengzhou? I know there is a factory____ your mother worked.
The rubbish _____ is produced every day is becoming a serious problem in cities around the world.
After Mandela was free (自由的) in 1990, he chose to shake hands with the people ________ wanted to kill him.
I’m a football fan. I was interested in everything _____is about the 2010 World Cup.
Do you know the teacher who is having an English lesson.