微分方程exy’=1的通解是______．
参考答案：y=C-e-x
________from other continents for millions of years, Australia has many plants and animals
not found in any other country in the world.[ ]
A. Being separated
B. Having separated
C. Having been separated
D. To be separated
在交谈时，不宜选择哪些话题?
