. The Roman Empire _____ for several centuries.
| A．exists | B．existed | C．was existed | D．is existing |
______ world’s largest retailer, Wal-Mart, has opened its ______ third store in Beijing, which means the firm now has 52 stores in China.
| A．The; a | B．A; a | C．The; the | D．The; / |
——Alvin, are you coming with us?
—— I’d love to, but something unexpected _______.
| A．has come up | B．was coming up | C．had come up | D．would come up |
Walmart, which is one of the largest American supermarket chains, _______ some of its store open 24 hours on Mondays through Saturdays.
| A．keep | B．keeps | C．have kept | D．had kept |
He is a very careful man, but he ________ make mistakes which seem ridiculous
| A．can | B．must | C．may | D．will |
One of our rules is that every student _______ wear school uniform while at school.
| A．might | B．could | C．shall | D．will |