① Are these all ours? ____ A. It is Zhang Peng's.
② Whose is it? ____ B. Yes,it is.
③ Is this yours?____ C. Yes. they are.
蚯蚓的运动是仅靠刚毛完成的.(判断对错)
下列四图中,能正确反映世界人口增长的是( )
粗盐提纯实验中,搭建蒸发装置时,下述操作中应首先进行的是( )
已知函数f(x)=2-|x|,则∫-12f(x)dx=( )