考博英语语法：动名词、分词、不定式

嘎嘣脆

动名词、分词、不定式。
主动或被动。(doing/done, to do /to be done)
发生在谓语动词之前还是之后。(doing/ having done /having been done, to do/to have done /to have been)

To在什么情况下作介词，什么情况下作不定式引导词。
真题剖析
(2000) … In the inner cities of America, newspapers regularly report on newborn babies  60  into garbage bins by drug-addicted mothers.
60. A. dropped  B. to drop  C. dropping  D.drops
(2001.3) A heroin addict, for instance, leads a  59  life: his increasing need for heroin in increasing doses prevents him from working, from maintaining relationships, from developing in human ways.  
59. A. destructive   B. dissatisfied    C. damaged     D. derivative