-Clark, your room is really in a mess, It needs ____
-Sorry , mum . I’ll do it at once
A:clean
B:cleaned
C:to clean
D:to be cleaned
Y×4=____ a×b=____ X×Y×7=____
下列哪种细胞的分裂属于无丝分裂( )
函数f(x)=2xx2-1-1x-1,x>1m,x≤1,在x=1处连续,则实数m=( )