...1.表示时间:now,then,suddenly,before,afterwards,later,so... | 2.表示空间顺序:first,secondly, far,above,below,near,beside,to the right,on one side... | 3.表示目的:for this purpose,for this reason,so that......
第二层次(其次)
...主要因素是: The main factor is that...... | B 第二层次(其次): Second, Secondly, In the second place, Next, Then , For another | 另一种方法是......Another means of ......is to .........