_________ that he had fallen behind, he tried to work harder.
According to a new survey carried out by an American university, learning______ second language can result in_______ increase in the power to learn your native tongue.
Mary, remember to bring the CD I want next time, _______?
Look! She is coming here and there _________.
–I could not start my car this morning due to the cold weather.--No wonder you were late. You ___ have used mine. I was not using all the morning.
Only by reading more books improve your reading skills.