I like getting up very early in summer.The morning air is so good ________.
A．to be breathed B．to breathe
C．breathing D．being breathed
Professor Williams keeps telling his students that the future ________to the well－educated.
A．belongs B．is belonged
C．is belonging D．will be belonged
The water ________ cool when I jumped into the pool for morning exercise.
A．was felt B．is felt C．felt D．feels
—What's that noise?
—Oh，I forgot to tell you.The new machine ________.
A．was tested B．will be tested
C．is being tested D．has been tested
—Why does the lake smell terrible?
—Because large quantities of water ________.
A．have polluted B．is being polluted
C．has been polluted D．have been polluted
His sister left home in 1998，and ________ since.
A．had not been heard of B．has not been heard of
C．had not heard of D．has not heard of
