(Over) (the past) few years, medical researchers (are searching) for a means (to

游客2025-03-16 30

问题 (Over) (the past) few years, medical researchers (are searching) for a means (to control) AIDS virus

选项 A、Over
B、the past
C、are searching
D、to control

答案 A

解析应改为have been searching。根据前后句意应该用现在完成进行时have been searching表示过去发生的事持续到现在。

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(Over)(thepast)fewyears,medicalresearchers(aresearching)forameans(to