To facilitate understanding the teacher should outline that there are two basic present tenses one the simple and one continuous or progressive.
帮助学生加强理解，老师应该概括归纳现在时的两种基本形式，就是一般现在时和现在进行时。
The present invention has the advantages of simple technics, convenient operation, good repeatability, and capability of continuous fabrication.
本发明方法具有工艺简单，操作方便，重复性好，可 连续化生产等优点。
It has the advantage of simple process, low cost. It also can be used for making high-precision bent tube or repairing present continuous-cast crystallizer.
工艺简单且成本低，不仅可以用来制造连铸结晶器，也可适用于制作高精密度的弯管及修复现有的连铸结晶器。
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