Great measures ______ to prevent the air pollution, but the sky is still not clear.
A. is taken B. are taken
C. has been taken D. have been taken
His stepmother did what she could _____ him．
A．help B．helping C．to help D．in helping
Do you know the most interesting story __________ took place long ago．
A．which B．that C．who D．×
Living in a house on a mountain top ______ be rather cold,
especially in winter.
A. can B.
shall C. need D.
should
_______ a reply from Mabel, Jack sent another e-mail to her.
A. Not receiving B.
Having not received
C. Not
received D.
Not having received
The question under discussion here is ______ of the "white
pollution".
A. that B. which C.
one D. it
