A:ca
B:may
C:will
D:shall
This is Mr White's ________ trip to Beijing. He has been there twice before.
小李同学的爸爸利用闲置资金购买了5万元股票,获得2千元股息。2千元属于 ()
细胞工程的理论基础是细胞的全能性。下列哪种细胞的全能性最高?( )