By the time a child is five, he _______ hundreds of hours of television.
He looked at the envelope(信封) and _____ Jenny’s handwriting immediately.
American English has changed _______ the centuries. There are several reasons _____ this.
The little boy fell asleep while ______TV. So his mother sent him to bed at once.
---Look! The telephone is broken. Someone damaged it ________ purpose. ---That may be right. But perhaps it was broken _________ accident.
Recently our government policymakers are very ______ about the rapidly rising food cost.