题目内容
(2010·江苏赣榆县城头高级中学高三第一次调研考试) 23. Doctors say it will be many years ___________ scientists develop an effective treatment for AIDS.
A. when B. since C. before D. as
C
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(2010·江苏赣榆县城头高级中学高三第一次调研考试) 23. Doctors say it will be many years ___________ scientists develop an effective treatment for AIDS.
A. when B. since C. before D. as
C