With the fast development of computer and Internet technologies, traditional printed books ______ by the growing popularity of online reading of e-books.
| A．are challenged | B．have challenged |
| C．are being challenged | D．have been challenged |
.________ that he had wasted a lot of time, Tom decided to work hard on his study.
| A． Realizing | B．To realize | C．Realized | D．Having been realized |
While watching television,________________________.
| A．the doorbell rang | B．the doorbell rings |
| C．we heard the doorbell ring | D．we heard the doorbell rings |
The reason why I want to write this review is to warn future travelers on how to avoided ________________ by those salesmen.
| A．being cheated | B．cheating | C．to cheat | D．to be cheated |
With lots of papers to read, he ____________ to the cinema.
| A．mustn’t | B．mustn’t have gone |
| C．couldn’t go | D．couldn’t have gone |
I have been working here since I _______ this new position.
| A．offered | B．have offered | C．was offered | D．had been offered |