Let us hope we can settle the matter without ______ more trouble.
A. any
B. a little
C. some
D. little
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He was disappointed to find his suggestions ______.
A. been turned down
B. turned down
C. to be turned down
D. to turn down
The rice ______ if you had been more careful.
A. would not be burning
B. would not burn
C. would not have been burnt
D. would not burnt
According to the story, the game of chess was invented by（）
A. an American Indian
B. an ancient Indian official
C. an Indian king
D. an Indian officer
一混合物的组分A和B在2.0cm长的色谱柱上的保留时间分别为16.40分钟和 17.63分钟，而两个色谱峰宽分别是1.11分钟和1.21分钟。则其分离度R等于
A. 1.06
B. 1.60
C. 0.95
D. 1.50
E. 1.78
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