Is Jenny skating?[ ]
A. Yes, Jenny is.
B. No, she is.
C. Yes, she is.
答案:C
_____ he wasn’t ready in time, we went without him.
A.Since
B.As
C.For
D.Because of
下列哪种物质是大气中的二次污染物?()
A.SO2
B.H2S
C.CO2
D.O3
E.NO