A:12-4=8(道)
B:12-8=4(道)
C:12+8=20(道)
D:4+8=12(道)
下列哪项不能鉴别一细胞是植物细胞还是动物细胞( )
下列化学用语与所表述的意义相符的是( )
①2Ca2+﹣﹣2个钙离子 ②O2﹣﹣2个氧原子 ③2H2O﹣﹣2个水分子
④2H﹣﹣2个氢元素 ⑤N20﹣﹣氮气中氮元素的化合价为零.
After studying in a medical college for five years,Jane________her job as a doctor in the countryside.
My Family