影响我国气候的因素,主要有( )
①纬度位置 ②寒流 ③海陆位置 ④地形.
A:①②③
B:①③④
C:②③④
D:①②③④
He is organized and is often . I hope he will have more at his business.
在平行四边形ABCD中,若AB=8cm,BC=6cm,则平行四边形ABCD的周长是( )
下列函数,①y=2x,②y=x,③y=x﹣1,④y=1x+1是反比例函数的个数有( )
— Well, it's hard to say, probably great, or maybe not.
用数学归纳法证明:1+122+132+⋯+12n2<2-12nn∈N*,第二步证明“从k到k+1”,左端增加的项数是( )