相邻两齿的同侧齿廓之间的分度圆弧长是()。
A.齿厚
B.槽宽
C.齿距
D.齿宽
参考答案:C
We had to be patient because it ________ some time ________ we got the full results.
A.has been;since
B.had been;until
C.was;after
D.would be;before
下列表述与化学用语对应且正确的是( )
A.CO2的比例模型:
B.氢化铵(NH4H)电子式:
C.
的名称:2,3-二甲基-4-乙基己烷
D.乙酸乙酯的水CH3COOCH2CH3+H218O 酸△ CH3COOH+CH3CH218OH