下列物质的沸点比较中,错误的是
A.F2<Cl2<Br2<I2
B.Li>Na>K>Rb>Cs
C.PH3<AsH3<SbH3<NH3
D.H2S<H2Se<H2Te<H2O
答案:C
Ten minutes ago, there ________ an eraser, a pen and some books on the desk.
A. was B. were C. is
接到事故报告后,企业负责人必须立即赶到事故现场,组织事故抢救。