中国面积最大的省区是新疆维吾尔自治区，有160万平方公里。[ ]
√
There are some trees ______ our classroom. [ ]
A. in front
B. in the front of
C. in front of
D. front of
A．a为动滑轮，B端钢缆受到滑轮组的拉力大小约为3G
B．a为动滑轮，B端钢缆受到滑轮组的拉力大小约为G
C．a、c为动滑轮，B端钢缆受到滑轮组的拉力大小约为3G
D．a、c为动滑轮，B端钢缆受到滑轮组的拉力大小约为G
G
G