—Why haven’t you asked her to come here?
—She _______ an important experiment when I found her and she _____ it.
| A．had done ; didn’t finish | B．was doing ; hasn’t finished |
| C．did ; wouldn’t finish | D．did; hadn’t finished |
Was it midnight ________ the fire broke out?
| A．when | B．that | C．which | D．at which |
— ________ he ________ anything about this historic site?
— Yes. That’s why he suddenly becomes so obsessed with it.
| A．Has; read | B．Does; read | C．Did; read | D．Had; read |
You should never base anything on a theory that _________ impractical in practice.
| A．is proved | B．prove | C．proves | D．proved |
With my hand-held Reader, I’ve read more books in the past six months than I ________ in the past six years.
| A．doing | B．did | C．have | D．do |
Since then, more than 2 billion apps have been downloaded at prices ________ free to $900.
| A．ranging between | B．ranging from | C．rang between | D．rang from |