详解ago与before的语法难点 1. before还是ago? 要说： I came to Manchester two weeks ago.I came to Manchester two weeks ago. 不要说： I came to Manchester before two weeks. Use “past time + ago" ago用于一般过去时，例如： 10 years ago, a long time ago, a few weeks ago, a couple of days ago Use "before + action / event" before用于动作或事件前，例如： before you left, before we start, before lunch 2. fall 还是reduce? These two words are the opposites of 'rise' and 'raise': 它们是rise和raise的反义词： something falls (e.g. the price fell) somebody reduces something (e.g. the company reduced the price) You will probably use 'fall' to describe numbers on a graph or chart for IELTS Writing Task 1: 在雅思短作文中，你可以用fall来描述图表里的数字。 In 20XX年, the number of customers fell. (verb, past) 这里的fall是动词，过去时。 There was a sharp fall in Internet usage. (noun) 这里的fall是名词。 'Reduce' and 'reduction' are probably more useful for Writing Task 2: reduce和reduction在长作文中更有用： We need to reduce the amount of pollution from exhaust fumes. (verb) reduce，动词。 Recycling leads to a reduction in waste. (noun) reduction，名词。 3. because还是because of? Compare these two sentences: 比较下列两个句子： I stayed at home because the weather was bad. I stayed at home because of the bad weather. The important difference is the use of the word 'was' in the first sentence. After 'because', you need a subject and a verb (e.g. the weather was). After 'because of', we don't use a verb, only a noun, nouns or noun phrase. 重要的区别在于第一句里使用了word。Because后面需要加主语和 动词(例如the weather was)。Because of 后面不需要动词，只要一个或多个名词，又或者名词词组就可以了。 本文来源：https://www.wddqw.com/doc/a7d778b229160b4e767f5acfa1c7aa00b42a9dd9.html