Up to now they enough money for students who can’t afford to go to school.A. are raisingB

问题补充：

Up to now, they enough money for students who can’t afford to go to school.

A. are raising

B. have been raising

C. have raised

D. had raised

答案：

A. are raising

B. have been raising

(答案→)C. have raised

D. had raised

解析：考查时态。本题的关键词是句中的up to now，直到现在；该时间状语与现在完成时使用。句意:直到现在，他们已经凑集到了足够的钱来帮助那些无法上学的孩子。故C正确。