$23. \_\_\_\_\_\_ scientists have learned a lot about the universe, there is much we still don$’t know.
Answer key
C
_ _ _ _ _ _ scientists have l…——2015 高考英语第 23 题答案解析
2015_省自主命题（安徽）
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这道题真正考什么？
关键能力
单项填空
difficulty
Differentiating