关于非谓语动词（这类关于分词的短语也要掌握）
关于非谓语动词，这类关于分词的短语也要掌握！（带有连词或介词的分词短语）
分词短语可以用在某些连词或介词后面。
一、介词+分词短语
分词短语表示伴随状况或原因的时候，可加介词with或without。
A car roared past, with smoke pouring from the exhaust.
一辆小汽车呼啸而过，排气管冒出一团团黑烟。
The old man often takes a walk after supper with his dog following him.
She left the party, without a word said .
分词短语表示时间，可以在分词前边加on。
On hearing her son"s death, the bereaved mother broke out crying.
一听到她儿子死亡的消息，这位母亲放声痛哭起来。（on强调时间，相当于as soon as）
二、连词+分词短语
用在连词后边的分词短语作状语，相当于简化后的状语从句保留了连词。
Once deprived of oxygen, the brain dies. = Once it is deprived of oxygen, the brain dies.
一旦缺氧，大脑就会死亡。（once强调时间）
Be careful while crossing the road.（while强调时间）
After talking to you, I always feel much better.
Although exhausted by the walk, he continued his journey.（although强调让步）
Although usually living on or under rocks or on coral reefs, marine snails have been observed in a great variety of habitats.
Although still running in a number of cities, the electric trolley has for the most part fallen into disuse.
After having annoyed everybody, he went home.
他把所有的人都惹烦了之后就回家了。
If seen under a microscope, a fresh snowflake has a delicate six-pointed shape.
如果从显微镜下观察，新降的雪花有纤小的六瓣。
但表示原因的分词短语前不能加连词（如 because，for，since，as 等），往往加介词 with。
_______the temperature falling so rapidly, we couldn"t go on with the experiment.
A. With
B. For
C. As
D. Since
正确答案：A。