过渡词： 1）递进 furthermore, moreover, besides, in addition, then, etc 2）转折 however, but, nevertheless, afterwards, etc 3）总结 finally, at last, in brief, to conclude, etc 4）强调 really, indeed, certainly, surely, above all, etc 5）对比in the same way, just as, on the other hand, etc (I)说明原因型模块

（一） Nowadays ,there are more and more XX in some big cities . It is estimated that ( 1 ). Why have there been so many XX ? Maybe the reasons can be listed as follows. The first one is that ( 2 ) .Besides,( 3 ) . The third reason is ( 4 ). To sum up ,the main cause of XX is due to ( 5 ) .It is high time that something were done upon it. For one thing ,( 6 ).On the other hand ,( 7 ). All these measures will certainly reduce the number of XX .注释：

（1）用具体数据说明XX现象

（2）原因一

（3）原因二

（4）原因三

（5）指出主要原因

（6）解决建议一

（7）解决建议二