----It’s traditional in China to firecrackers on Spring Festival.----But the serious smog(雾霾)nowadays needs us to stop it.
Mr. and Mrs. Black ______ back _________.
——The dining room is dirty. Can anyone clean it? ——________ I do it all the time.
——Would you mind turning down the music? ——_____.
——Why is the classroom so dirty? ——Sorry, Sir. It _____ yesterday. We forgot to do it.
——Have the police caught the thieves _____ the bank last week? ——Yes, they were caught yesterday.