---- Is it in that factory __________ “Red Flag” cars are produced?
---- No, they are produced in our factory.
A．inwhich B．where C．which D．that
We’re talking about the piano and the pianist _____ were in the concert we attended yesterday.
A．which B．whom C．who D．that
The freezing point is the temperature __________ water changes into ice.
A．atwhich B．when C．inwhich D．ofwhich
Don’t talk about such things _______ you are not sure about.
A．which B．that C．as D．what
Hurry! The train _______. You know it _____at 8:30am. .
A．leaves; leaves B．is leaving; leaves
C．leaves; leaving D．is leaving; is leaving
With the help of high technology, more and more substances _________ in the past years.
A．discovered B．have discovered
C．had been discovered D．have been discovered
