1）与主语动词同时，
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. 刚一到那儿，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。
