And at the end of the solid rod is a mirror.
棒子尽头是一面镜子。
This paper compares the property of the hollow rod with that of the solid rod, and conducts case calculation.
将空心抽油杆与实心抽油杆进行了性能对比和实例计算，由此分析出空心抽油杆在螺杆系井中应用的优越性。
This paper compares the property of the hollow rod with that of the solid rod, and conducts case calculation.
将空心抽油杆与实心抽油杆进行了性能对比和实例计算，由此分析出空心抽油杆在螺杆系井中应用的优越性。
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