It may start with a concrete anxiety: Did I lock the back door?
它可能始于某个具体的焦虑：后门锁上了没有？
2
To seize the space debris, the mechanical arm need to lock the concrete goal, but in space, debris is changing position.
要抓住太空碎片，这只机械手臂需要锁定具体目标，但在太空中，碎片是不断变换位置的。
3
The paper presents various temperature control measures taken in ground concrete placement at permanent lock of Three Gorges Project during summer construction of 1999 .