Great changes have taken place in that school. It is no longer ___ it was 20 years ago, ___ it was so poorly equipped.
| A．what, when | B．that, which | C．what, which | D．which, that |
18. I used to be a very delighted girl. I guess no human being could have passed _______ childhood.
| A．a happy | B．a happier | C．the happier | D．the happiest |
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 |