Scientists have decided to declare war on AIDS in order to make breakthrough in treating

Scientists have decided to declare war on AIDS in order to make breakthrough in treating it.
A. a, a
B. /, a
C. a, the
D. / , the

A. a, a(答案→)B. /, aC. a, theD. / , the解析：考查冠词：句意：科学家已经决定向艾滋病宣战，为了在疗法上有突破。第一空不填，declare war on对…宣战，第二空填a， make a breakthrough有突破，选B。

这下我知道了