2.1.3 等立连接词

1．连接词and

1）and可以用于连接单词、短语和短句，表示“和，因此”等意思。

例句1:Certain materials, such as gold and copper, have many free electrons. And some materials have practically（几乎）no free electrons.

例句2:Water has weight and occupies space.

例句3:When a voltage is applied across two ends of a wire, many free electrons progress（前进）along the wire and a current results.

2）与相关的动词例如stop, try, go, come等连接。

例句：We can go one step further and take into account（考虑）the nonzero resistance of the actual surface.

3）当祈使句结合and一词时就等同于if条件句。

例句：Try hard, and you will solve this puzzle.

= If you try hard, you will solve this puzzle.

译文：如果你坚持，你就能解决这个难题。

4）表示一般语气和强调语气的句型。

当表示一般语气的时候：使用结构A, B, C（,）and D；而当表示强调语气的时候，采用A and B and C and D的形式。

2．连接词or

1）连接词or，通常表示“或者”的意思。

例句1:This model should be compared with the ideal, or desired model.

译文：应该把这个模型和理想或者渴望的模型相比较。

例句2:There are three main laws of mechanics（力学）or three laws of Newton（牛顿）.

译文：力学里有三大主要定律，或称为牛顿三大定律。

例句3:Computers are particularly useful in such research field, where signals must be quickly recorded or they will be lost.

2）在．.. +necessary（imperative, essential, important, must）+... or ..．的句型中表示“不然就怎么样”。

例句：It is important for the reader to learn and understand the basic concepts and operations presented here, or the development and the applications of later topics will be difficult to comprehend（理解）.

译文：学习和理解这里讲解的概念和操作对读者很重要，不然理解后面主题的发展和应用就会有困难。

3）表示一般语气和强调语气的句型。

当表示一般语气的时候，采用A, B, C , or D。

例句：R, G, or B video voltage indicates information of that color.

而当表示强调语气的时候，采用A or B or C or D。

例句：R or G or B video voltage indicates information of that color.