— I’d better__________ now．The water is boiling in the kitchen．
— Good-bye．
A．ring off B．ring up C．ring in D．ring back
Only by shouting at the top of his voice__________．
A．he was able to make himself hear
B．he was able to make himself heard
C．was he able to make himself hear
D．was he able to make himself heard
—Must I give the pen to the manager ?
—No, you may give it to________you think is on duty in the office ．
A．whomever B．no matter who
C．whoever D．who
Look! The dictionary, ________cover is red, is a birthday gift given by Tom．
A．which B．whose C．its D．where
_______environmental damage is done, it takes many years for the ecosystem to recover．
A．Even if B．If only C．While D．Once
Every possible means _______to prevent the air pollution, but the sky is still not clear．
A．are being used B．have been used
C．has been used D．had been used
