The production of these biofuels, such as ethanol made from maize, has risen sharply recently, （） the replacement of food crops with fuel crops has been heavily criticized.
A.but
B.and
C.when
D.or
正确答案：but
The production of these biofuels, such as ethanol made from maize, has risen sharply recently, （） the replacement of food crops with fuel crops has been heavily criticized.
A.but
B.and
C.when
D.or
正确答案：but