若2m=3,2n=4,则2m+n等于______.
∵2m=3,2n=4,
∴2m+n=2m•2n=3×4=12.
故答案为12.
Thanks _____ your help, and now I have made great progress in my English. [ ]
A. to
B. with
C. for
D. by
金属矿床地下开采时,一般按()、()与()三个步骤进行,各步骤之间保持一定的时空超前关系,每一步为下—步创造条件。准备出适当的矿量。