According to the latest investigation,most mistakes be prevented if students are careful enough.
__________ parents say and do has a life-long effect on their children.
__________ matters most in learning English is enough practice.
Choosing the right dictionary depends on __________ you want to use it for.
Having checked the doors were closed, and ___ all the lights were off, the boy opened the door to his bedroom.
It is none of your business __________ other people think about you. Believe yourself.