Researchers claim to have found the firstproof _______ getting a regular eight hours a night really does make you appearhealthier and more attractive.

To understand the grammar of the sentence, you must break it into parts

．Nobody but doctors or nurses and those ________ by Dr. Hu ________ to enter the patient’s room.

Haze weather has become common in some major cities in China. We all wonder ________.

The law says that all public buildings must be accessible to people who have trouble _____.