The traffic rule says young children under the age of four and less than 40 pounds must be in a child safety seat.
We'd better set off or it will be dark __________ we know it.
I ___________in the No.8 Middle School for three years, and I have been in this school for one and a half years.
Preparations are being made for the Olympic Games ______ in Brazil in 2016.
Mr Green has two daughters, both of____ are doctors.
_____from what he said, he must be the thief who has stolen the car.