—I'm sorry I'm late. I got in the traffic on my way here. —It's OK, we've just started.
A:filled up
B:held up
C:brought up
D:taken up
分解因式:a2+a=____.
下列各项,不属于地图基本要素的是( )
鱼能够在水中呼吸,是因为水中的氧能进入鱼体内,其途径是( )