______ is no need for primary students to work attheir desks all the long.

When I needed his help, my roommate just stood by and did nothing.—_______He appears to be a warm-hearted person.

province in China was attacked bysuch a terrible drought this early spring ____________few people hadexperienced before, ____________ made us worry about global climatechanges

How much of the city have you _________ since you came to work here?

You go through the security check（安检）before getting on the train.