15. _______ all the inventions have in common is _____they have succeeded.
A. What; what B. That; that C. What; that D That; what
The discussion _______ alive when an interesting topic was brought in.
| A．was coming | B．had come |
| C．has come | D．came |
Because the shop _______, all the T-shirts are sold at half price.
| A．has closed down | B．closed down |
| C．is closing down | D．had closed down |
—I’m sorry,but there’s no smoking on this flight.
—Oh,I _______ that.Sorry, I won’t again.
| A．don’t know | B．didn’t know |
| C．won’t know | D．haven’t known |
—Why did you leave that position?
—I _______ a better position at IBM.
| A．offer | B．offered |
| C．am offered | D．was offered |
—What were you doing when Tony phoned you?
—I had just finished my work and _______ to take a shower.
| A．had started | B．started |
| C．have started | D．was starting |