凡是收文对象无法限定或无须限定时,公文的主送机关一项可以省去。()
参考答案:对
下列各组比较不正确的是( )
A.酸性:H4SiO4<H3PO4<H2SO4<HClO4
B.碱性:Be(OH)2<Mg(OH)2<KOH
C.氧化性:S<O2<F2
D.还原性:Se2-<S2-<O2-
There_____pens in the pencil case and there ______a computer on the desk. [ ]
A. are; is
B. is; are
C. is; is
D. are; are