这种结构主要用于书面英语。
目前分词可代替as/since/because+ 主语+ 动词，即分词可
帮助讲解其后面所发生的动作：
Knowing that he wouldnt be able to buy food on his journey he tooklarge supplies with him．等于：
As he know
他了解路上买不到食物，就带了不少食物。
Fearing that the police would recognize him he never went out in day-light．等于：
As he feared
由于害怕警察认出他来，他从不白天外出。
注意：当 being坐落于句首时，一般意为 as he is或as he was（因为他是）：
Being a student he was naturally interested in museums．等于：
Because/As he was a student
他作为一个学生，自然对博物馆有兴趣。
这里 being a student的意思并非while he was a student（在他学生年代）。
如此用的分词的主语并未必要与跟在后面的动词的主语相同。它可以带有我们的主语：
The day being fine，we decided1 to go swimming．
天气好，大家决定去游泳。
在这样的情况下分词需要跟在作其主语的名词/代词之后。Be-ing fine the day，we decided是不对的。但 Being athletic，Tom found the climb quite easy（作为运动员，汤姆感觉这次爬山很容易）是正确的，由于汤姆同时是found和后面跟着的climb的主语。
同一个句子中可以连着用两个或两个以上的目前分词：
Realizing that he hadnt enough money and not wanting to borrow fromhis father，he decided to pawn2 his watch．
了解自己钱不够，又不想从爸爸那里借钱，他决定把手表当掉。
Not knowing the language and having no friends in the town，he found ithard to get a piece of work．
既不懂当地语言，在此城又没朋友，他发现自己非常难找到一份工作。
