We’ll go to the park to have s picnic ____ it rains.
A. if
B. unless
C. besides
D whether
—____________you swim? —Yes，but I’m not a good swimmer.
| A．Can | B．May | C．Need | D．Must |
Mr. Green ____________ to the manager now. You’d better call him later.
| A．talk | B．talked | C．is talking | D．was talking |
Tian’anmen Square is one of ____________ squares in the world.
| A．large | B．larger | C．largest | D．the largest |
There ____________ many students in the library after school every day.
| A．has | B．have | C．is | D．are |
Lee came to Beijing in 2005.He has been here ____________ than you.
| A．long | B．longer | C．longest | D．the longest |