问题
选择题
I hear our teacher will be back _____ three weeks' time. [ ]
A. at
B. in
C. for
D. after
答案
答案：B
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I hear our teacher will be back _____ three weeks' time. [ ]
A. at
B. in
C. for
D. after
答案：B
2Fe（s）＋3CO2（g）ΔH＞0
粉末的密闭容器中通入CO气体，10min后，生成了单质铁11.2g。则10min内CO的平均反应速率为 