We are living in an age _______ many things can be done on computers and the Internet.
| A．which | B．that |
| C．whose | D．when |
17. The new outline will throw light _______ students’ understanding of history.
| A．upon | B．at | C．of | D．Over |
--- Well, Linda, I’m sorry but I have to leave.
--- _______. I hope to hear from you soon.
| A．So am I | B．Enjoy yourself | C．Don’t be so sad | D．Keep in touch |
15. Researchers _______ to develop vaccines and this will probably take several months to complete.
| A．are working | B．worked | C．will work | D．has worked |
14. Water can absorb and give off a lot of heat, thus ________ a stable environment.
| A．creating | B．to creat | C．created | D．being created |
13. He took ________ advantage of cultural resouces and succeeded in ________ 1990s.
| A．an ; / | B．the ; the | C．an ; the | D．/ ; the |