Mary had to call a taxi because the box was ________ to carry all the way home.

The government has been under growing pressure to ________ the causes of air pollution as smog frequently smothers the country’s large cities.

The Chinese University of Hong Kong, founded in 1963, ______ 50 in 2013.

(2014·沈阳模拟)—Any advice for me?—You’d better________the timetable to see when the train leaves.

The president spoke at the business meeting for nearly an hour without _________ his notes.