中低压玻璃钢承插连接管道，单口试压完成后，（）不能移动。
参考答案：连接部位
The teacher said that _______ of the boys would take part in the talent show. [ ]
A. three five
B. three fives
C. thirds fifths
D. three fifths
型钢按产品（）分为大型、中型、小型材。
A．断面形状
B．材质
C．断面尺寸
D．用途
