下列各物质中，键和分子都有极性的是（）。
A.CO2和SO2
B.CCl4和Cl2
C.H2O和SO2
D.HgCl2和NH3
参考答案：C
What can you see _____ the room?[ ]
A. on
B. in
C. at
D. to
—How did you like Nick’s performance last night —To be honest，his singing didn't ______ to me much．
A．appeal B．belongC．refer D．occur
