Don't leave the lights on all night, you will waste electricity.
If ______________________________________________________________________________

English is easy to learn.
It ______________________________________________________________________________

She had to do the washing up but she didn't.
She forgot _______________________________________________________________________

It may rain hard this afternoon, so take the rain coat with you.
In case _________________________________________________________________________

Their trip lasted three day.
They had ________________________________________________________________________

When did you first know him?
How ___________________________________________________________________________

The children couldn't go swimming because the sea was very rough.
The sea was too __________________________________________________________________

They think the owner of the house is abroad.
The owner _______________________________________________________________________

It's a pity you didn't tell us about this.
I wish __________________________________________________________________________

It is a three-hour drive from Hanoi to Namdinh.
It takes _________________________________________________________________________