I saw Helen at the party last month. It _________ a year since we met last time.
The way of life he was used to _______ when he came to study in America.
He said that we should protect the ancient civilization from _______.
She told us what she bought yesterday ________ a few apples and some clothing.
Do you know that Yuan Longping is known as ______ father of hybrid rice (杂交水稻)?
He didn’t come to school yesterday _______ that he was ill.