东北三省农业结构完整,其中占主导地位的农业部门是( )
A:种植业和畜牧业
B:林业和畜牧业
C:种植业和林业
D:种植业和渔业
________ is difficult for them to finish the work in two days.
As a doctor, have you got ___________ to say about Jack?
已知三角函数值,可以先利用计算器求出锐角α与β,从而比较它们的大小.你能否不用计算器来比较以下的锐角α与β的大小?如果能,说说你的想法.
(1)cosα=34,tanβ=54;
(2)sinα=0.456 7,cosβ=0.567 8.