介词是TOEFL试题中比较活较的词性，而且具有一定的难度。中国学生一向对介词感到束手无策，因为英文介词种类繁多且词意多变。不过，TOEFL涉及的有关介词的题目重复性很强，而且有规律可循。只要考生善于总结、记忆，还是可以保证得满分的。介词的题目主要分布在Written Expression(16－40题)中，命题焦点售在中（1）含有介词的固定短语，（2）含有特定含义的介词误用

　　介词常考题型及解题要点

　　1.含有介词的固定短语：短语或词组中的介词不能随意更换或省略

　　全真例题分析

　　（1）Most aquatic animals breathe by means external respiratory organs called gills.
(答案)C 正确的短语为by means of,其中的介词of不能省略

　　（2） Speed refers only toward the rate of mution without
specifying any direction of motion.(94.8)
(答案)A 正确短语形式为refer to

　　（3） Historical geology deals about data on the development of the Earth
gathered from the study of rocks, which are analyzed to determine their age and composition. (93.8)
(答案) A正确短语式式为deal with.

　　（4）The diamond is the only gemstone composed with just one chemical element, carbon.
(答案) A 正确短语形式为。Be composed of

　　（5） Best known for his research in statistical mechanics and meson physics. Chen Ning Yang shared the Nobel Prize in 1957 to another physicist from the United States, Tsung-dao Lee.
(答案) C 正确的短语搭配为 share.......with

　　（6）The doctrine of eminent domain is based the legal tradition that all real property is subject to the control of the state.
(答案) A 正确的短语形式为be based on 其中的介词on不能省掉。