研究问题、目标和意义应当在研究报告的()部分提出。
A.标题
B.导论
C.文献回顾
D.研究方法
参考答案:B
解析:根据《教材》,研究问题、目标和意义应当在研究报告的导论部分提出。
将Cu片放入0.l mol / L FeCl3溶液中,一定时间后取出Cu片,溶液中c(Fe3+)∶c(Fe2+)=2:3,则Cu2+与Fe3+的物质的量之比为
A.3 : 2
B.3 : 5
C.4 : 3
D.3 : 4
When the young man realized that the police had spotted him, he made () the exit as quickly as possible, only to find that two policemen were waiting outside.
A.off
B.from
C.towards
D.for