doing 在这个句子中作什么成分？ 为什么用doing?
If you become rich, you will have a difficult time knowing who your real friends are. 这里的 doing 在句子里是什么成分？ 为什么用doing?
If you become rich, you will have a difficult time knowing who your real friends are. 这里的 doing 在句子里是什么成分？ 为什么用doing? 注意：其实这一句也可以表述为If you become rich, you will have a difficult time (in) knowing who your real friends are. 再如：I spent half an hour (in) doing my homework. 介词后面跟动词ing形式。 现在明白了吗？
have a good/difficult time in doing sth have difficulty in doing sth have problems in doing sth have trouble in doing sth have fun in doing sth 动名词短语做介词in 的宾语，表示“在做某事的过程中”，在以上搭配中，介词in 都可省略。
另外，还可用介词“with +名词”替换in doing sth。 I had much difficulty (in) finding his house。 我费了很大劲才找到他家。 We will have a lot of fun (in) learning English。
在学英语过程中,我们会得到很多乐趣。 He had many problems with his homework。 他做作业遇到了很多问题。
knowing who your real friends are是现在分词短语，做time的定语！！！ 动词做名词的定语时可以有三种形式，doing 和 to do和done,done是被动形式下用，doing \ to do 是主动形式，不同的是，doing表示的是一种状态，to do 表示的是一个动作，此题know，明显是表示状态的动词，所以用doing
If you become rich, you will have a difficult time knowing who your real friends are. 假如你变的富有，你将很难知道谁是你真正的朋友。 句knowing who your real friends are是现在分词短语，做状语
答：给你介绍一个实用的英语语法网站，希望会对你学英语有所帮助详情>>
答：B 被动语态，be found to do. A中的made与found均为过去分词，冲突！详情>>
问：hArd work 和hArd--working有什么区别
答：一个是名词 一个是形容词撒详情>>
