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
查看答案
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
The passengers were robbed ______ all their money.
A. of
B. off
C. from
D. away
This story tells us （）
A. how cruel the king was
B. how clever the minister was
C. Sissa was a famous mathematician
D. how the game of chess came into being
网络图中的箭线应保持( )。
A. 从右向左的方向
B. 从上到下的方向
C. 循环方向
D. 从左向右的方向
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