A:①②③
B:④⑤⑥
C:③④⑤
D:②③⑥
在解决国际经济贸易争端方面,____发挥着重要作用;开展国际经济合作的基本原则是____。
用反证法证明命题“在直角三角形中,至少有一个锐角不大于45°”时,应先假设( )
选择单词,补全短文
hot China winter people old east
Shanghai is the biggest city in ____.It's in the ____ of China. It's got a lot of ____.It's an ____ city. It's very ____ in summer and it's cold in ____.