Some children are coming out of the building. Some of them ____ into the park.
A. go
B. is going
C. are going
D. going
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The door is open. Sam is going ____ it.
A. to shut
B. shut
C. to shutting
D. shuts
What ____ the children ____? They are jumping off the tree.
A. is, doing
B. are, doing
C. are, do
D. do, do
圆轴扭转,其上各点都处于纯剪切应力状态
A. 对
B. 错
栅格图矢量化,将矢量化的dwg,文件上交(不需交原来的栅格文件),并将矢量结果通过打印输出,导出pdf格式或.jpg格式(图的右下角注记:姓名,学号),要求对页面设置,打印比例尺正确。