the editor at once sent the journalist a fax instructing him to find out the exact

题目

the editor at once sent the journalist a fax instructing him to find out the exact
number of steps and the height of the wall.
请问instruct为什么在非谓语上,加ing形式,如果是加变成 to instruct 可以吗,

答案

1 如果是 to instruct,强调的是目的“为了- - - ”.如果这麼用,语法没有错.
2 instructing在你的句子裏面是分词结构,这个动作与sent同时发生,and instructed.
如果是and instructed的话,就与sent 并列了.