詳解ago與before的語法難點
1. before還是ago?
要說：
I came to Manchester two weeks ago.I came to Manchester two weeks ago.
不要說：
I came to Manchester before two weeks.
Use "past time + ago"
ago用於一般過去時，例如：
10 years ago, a long time ago, a few weeks ago, a couple of days ago
Use "before + action / event"
before用於動作或事件前，例如：
before you left, before we start, before lunch
2. fall 還是reduce?
These two words are the opposites of 'rise' and 'raise':
它們是rise和raise的反義詞：
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來描述圖表裏的數字。
In 2008, the number of customers fell. (verb, past)
這裏的fall是動詞，過去時。
There was a sharp fall in Internet usage. (noun)
這裏的fall是名詞。
'Reduce' and 'reduction' are probably more useful for Writing Task 2:
reduce和reduction在長作文中更有用：
We need to reduce the amount of pollution from exhaust fumes. (verb)
reduce，動詞。
Recycling leads to a reduction in waste. (noun)
reduction，名詞。
3. because還是because of?
Compare these two sentences:
比較下列兩個句子：
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.
重要的區別在於第一句裏使用了word。Because後面需要加主語和動詞(例如the weather was)。Because of 後面不需要動詞，只要一個或多個名詞，又或者名詞詞組就可以了。
