—How unhappy your roommate looks!—Yes, but he's not willing to tell me what it is ________ is troubling him.
You should make ______ a rule to leave things______ you can find them easily.
Many people say______ is shown on television.
-----Is this the first time you______ Chengdu? -----No. But the first time I______ here, the city wasn’t so beautiful
Has the doctor _______ called for?
Mr Smith has a lot of business______. I know by______ that this man cannot be trusted.