谢谢各位老师的解答，下面的句子我有一些疑惑：
I wrote to over twenty companies askingfor work, but nothing came of my efforts.
为何句子中用asking for work 这个目前分词？我一直只了解write sb to do sth这个结构。
若是目前分词的话，这个句子的wrote 和asking 是同时发生的意思吗？
句子应该是i wrote to over twenty companies and ask for work. 后面把and去掉，最后成了 i wrote to overtwenty companies asking for work.
谢谢！
ing分词结构“asking for work”作状语还是作补语见仁见智！其实这种句型使用方法并不少见，前面可以加逗号，也可以不加逗号（你的这句没逗号）。而且用to ask也是对的，不定式表目的，这就非常明显了。举些例子看看：
1.Wingate wrote to his father, asking for more money. 这一句有逗号
2.I wrote to the Minister asking his advice on the forthcoming presidential election.（Collins COBUILD Dictionary of Phrasal Verbs第二版）
3.So I wrote to the government asking if they thought it fair that I was in this situation.
4.She wrote to her aunt asking for help.
5.Kim wrote to the university to ask for a catalog.这一句用的是不定式to ask
