1）一般式表示与主语动词同时发生。例如：
Hearing the news， he jumped with joy. 听到这一消息，他高兴得手舞足蹈。
Arriving there， they found the boy dead.一到那儿，他们就发现那男孩死了。
典型例题
The secretary worked late into the night， ___a long speech for the president.
A. to prepare B. preparing C. prepared D. was preparing
答案B. 此处没有连词，不能选D，否则出现了两个谓语动词worked和was preparing. 只能在B，C中选一个。又因前后两个动作同时发生，且与主语为主动关系，应用现在分词。
2）完成时表示先于主语动词发生。例如：
While walking in the garden，he hurt his leg. 在花园里散步时他伤了腿。
分词作时间状语，如果先与主动词的动作，且强调先后， 要用having done.
Having finished his homework， he went out. 做完作业后，他出去了。
=As he had finished his homework， he went out.
典型例题
___ a reply， he decided to write again.
A. Not receivingB. Receiving not C. Not having received D. Having not received
答案C. 本题考查分词的时态与分词的否定式。根据题意判断，分词的动作（接信）发生在谓语动词的动作（决心再写信）之前，因此用分词的完成式。分词的否定式的构成为not +分词，故选C.该句可理解为：Because he had not received a reply， he decided to write again.