A:一定是纯净物
B:一定是混合物
C:一定是单质
D:一定不是化合物
阴影部分的面积=____面积-____面积=____
9+____=11 9+____=17 9+____=13
11-9=____ 17-9=____ 13-9=____
- How long does it take to get to the airport?
- Forty minutes. But it's foggy today. I'm not sure _________ the highway will be closed soon. Let's set off earlier.