Warmblooded animals live an active life even in freezing winter, which helps them to________their normal body temperature. [ ]

I feel it hard to keep up with my classmates. Butwhenever I want to _______, my teacher always encourages me to work harder.

What ______ your father usually do after work

Everyone present certainly thinks there ______ be a total ban on cigarette advertising.

Last Sunday I went to visit the History Museum where I saw a pot _________ about 1,000 years before.