It was never clear
----What’s that building made of?
----____________, I think.
| A．Marble and stone | B．It has a garage |
| C．Very beautiful | D．It’s kind of modern |
. If I had got back 5 minutes earlier, I _________ him.
| A．would see | B．would have seen | C．will have seen | D．had seen |
With the rapid growth of Cyberspace, everyone should be encouraged to use ______ Internet as ______ tool, making it a trend to study in virtual schools in the future.
| A．不填；a | B．不填; the | C．the; the | D．the; a |
----Bruce, I really appreciate your painting. 
---- .
| A．I practice every day | B．Thank you very much |
C．No, I don’t think so | D．Well, it’s not good enough |
It was about 600 years ago __________ the first clock was made.
| A．that | B．until | C．before | D．when |