They'd better ______________ at two. [ ]
A. start
B. to start
C. started
D. starting
答案:A
设全集U=Z,集合A={-1,1,2},B={-1,1},则A∩(CUB)=( )
A.{1,2}
B.{1}
C.{2}
D.{-1,1}
老区水岗EA-128换热器的作用是什么?