Most of us found ______ difficult to finish the work in such a short time.
A．this B．which C．what D．it
—Do you know where Mary is?
—No, I don’t. I ______ her since last Sunday night.
A．haven’t seen B．didn’t see C．won’t see D．don’t see
You still go to the gym every day, ______ you?
A．do B．don’t C．are D．aren’t
The boy ______ is standing at the school gate is our monitor.
A．which B．whose C．who D．when
Alice wants to become ______ singer when she grows up.
A．不填 B．the C．an D．a
Modern science has given clear evidence ______ smoking can lead to many diseases.
A. what B which C. that D where
