一个完整句子通常由短语或从句组成，而句与句之间的连接部分就要使用连词。一个句子至少含有一个主句，所谓主句就是一个句子有主语，谓语，并且能独立存在而不以because、if等引导。一个句子可以有多个主句，但主句间不能用逗号连接而应该用连词进行连接，例如：

　　Wrong: I need to relax, I have so many things to do!

　　上面的句子可以修改为：

　　Right: I need to relax, BUT I have so many things to do!

　　像and 、but 、or 、for 、yet 、nor 、so 这些都是常见的并列连词。而and 又是最常见的连词，可以用来罗列事物如：apples, grapes, AND pears 也可以用来连接句子如：

　　I like apples, AND she likes grapes。

　　从属连词如：because 、although 引导从句，附属于主句。有时可以用逗号+从句来与主句进行连接，对主句进行说明：

　　◆ Right: I need to relax, BECAUSE I have so many things to do!

　　◆ Right: ALTHOUGH new data from the Labor Department indicate that producer prices rose rapidly last month, some analysts contend that the economic slowdown in the euro zone and in Asia will stem the rise in commodity prices, lessening inflationary pressures in the United States.

　　在连词的使用过程中，要注意不要过多的使用连词而丢失了主句：

　　◆ Wrong: ALTHOUGH I need to relax, YET I have so many things to do!

　　◆ Right: ALTHOUGH I need to relax, I have so many things to do!

　　◆ Right: I need to relax, YET I have so many things to do!

　　而在选择使用哪个名词的时候也要注意所选名词与句中的整体句意是否相符：

　　Wrong: She is not interested in sports, AND she likes watching them on TV.

　　上面的前后两个句子在句意上应该是相对的两个部分，所以可以换个连词来表达：

　　◆ Right: She is not interested in sports, BUT she likes watching them on TV.

　　◆ Right: ALTHOUGH she is not interested in sports, she likes watching them on TV.

　　下面是一些常见的连词：

　　Coordinating Conjunctions: For / And / Nor /But / Or / Yet / So

　　Subordinators: Although / Because / Before /After / Since / When / If / Unless / That / Though / While

　　我们再看一个例子：

　　Citizens of many countries are expressing concern about the environmental damage caused by the widespread release of greenhouse gases may be impossible to reverse.

　　在这个例子中，前半部分Citizens of many countries are expressing concern about the environmental damage caused by the widespread release of greenhouse gases 非常正确，但是剩下的部分may be impossible to reverse 的主语是谁?句意上来说environmental damage 是其主语，但是environmental damage 不可能既是about 的宾语又是may be 的主语。所以这个句子可以这样将about 改为that ：

　　Citizens of many countries are expressing concern THAT the environmental damage caused by the widespread release of greenhouse gases may be impossible to reverse.

　　另一种改法是在may be impossible to reverse 前面加入名词，这种在GMAT考试中非常常见，特别是一些指代不清的情况下，通常出题者会用逗号加名词来解释说明后面的部分：

　　Citizens of many countries are expressing concern about the environmental damage caused by the widespread release of greenhouse gases, DAMAGE THAT may be impossible to reverse.