计算(-3)2+4的结果是( )
A.-5
B.-2
C.10
D.13
(-3)2+4=9+4=13.
故选D.
有机过氧化物比无机氧化剂更容易分解,其分解温度一般在()以下。
A、150℃
B、200℃
C、250℃
____ that silver is not widely used as a conductor?
A.Why is
B.Is it why
C.Why is it
D.Why is that