— Why does the lake smell terrible?
— Because large quantities of water ____.
[ ]
A. have polluted
B. are being polluted
C. has been polluted
D. have been polluted
答案:D
— Why does the lake smell terrible?
— Because large quantities of water ____.
[ ]
A. have polluted
B. are being polluted
C. has been polluted
D. have been polluted
答案:D