分解因式:a2-a=______.
a2-a=a(a-1).
七大洲中跨经度最多的大洲是[ ]
A、亚洲
B、北美洲
C、非洲
D、南极洲
The plane leaves at 9:00 p.m. So I have to be at the airport __8:00 p.m. at the latest.
A.until
B.after
C.by
D.around