选修6 Unit 4 Global warming

重点句型

Some byproducts of this process are called “greenhouse” gases, the most important one of which is carbon dioxide.
这个升温过程的一些副产品就叫做“温室”气体，其中最重要的就是二氧化碳。
定语从句中的介词或介词短语可以提到引导词which, whom的前面。

The old man has three daughters, two of whom are teachers.
这位老人有三个女儿，其中的两个是老师。
Soon they arrived at a farm house, in front of which sat a small boy.
不久他们来到了一所农舍，农舍前坐着一个小男孩。

单项填空
I saw a woman running toward me in the dark. Before I could recognize who she was，she had run back in the direction _____ she had come.
A. of which                       B. by which
C. in which                       D. from which
解析：选D。介词的选择要依据搭配和句子意义。come from表示“来自……”; of与in不与come搭配;come by意为“从旁边经过”。