The among them and most important is a certain type core and the construction of the type, for example adopt the whole the type of type still, and their fixed position and tight way of.
其中最重要的是确定型芯和型腔的结构，例如是采用整体式还是镶拼式，以及它们的定位和固紧方式。
2
Maybe your shoulders are tight because you've been working in the same position for four hours straight.
或许由于你坐在同一个位置持续工作了4小时，你的肩可能会很酸。
3
When you do it in a standing position, keep your abs and lower back tight to support your spine.