从多边形一条边上的一点(不是顶点)出发,连接各个顶点得到2003个三角形,则这个多边形的边数为
A. 2001
B. 2005
C. 2004
D. 2006
答案:C
After the discussion the students asked their teacher ______ next. [ ]
A. which to do
B. what to do
C. how to do
在含有丙酮的空气中,含丙酮的体积分数是0.04,丙酮的比摩尔分数是()kmol(丙酮)/kmol(空气)
A.0.072
B.0.062
C.0.052
D.0.042