The world’s supplies of petroleum （）.
A、
have gradually exhausted
B、
are being gradually exhausted
C、
are gradually exhausting
D、
are gradually exhausted
【正确答案】：B
【题目解析】：
本题考察的是现在进行时的被动语态：石油正在逐渐地被消耗。exhaust是动词，消耗。主语是supplies 是复数，gradually 长期内逐渐地，慢慢地。
