下列物质属于纯净物的是( )
A:干冰
B:澄清石灰水
C:清新空气
D:加碘食盐
该图显示我国四个省2005年三种常规能源生产的相对比例(均已折算成标准煤)。读图,回答问题。
下列现象中会造成血压升高的是( )
给下列图片选择合适的对话。
A. - Do you like singing? - No. I like dancing.
B. - What are they? - They're snakes.
C. - Would you like some meat? - No. I like fish.
D. - Do you like pigs? - Yes. They're lovely.
分式bax3,c-3bx,a5ax2的最简公分母是( )