Though he is at home, he doesn't feel for he has many things to do.
A:alone; lonely
B:lonely; alone
C:alone; alone
D:lonely; lonely
猴的下列各组细胞中,肯定都有Y染色体的是( )
将∠α放置在正方形网格纸中,位置如图所示,则tanα的值是( )
下图为“美国和我国东北地区农业分布示意图”。读图回答下列问题。
512−16+23= ____