A. Reason

• I went home early because I was feeling tired.
• As/Since I was feeling tired, I went home early. (We don’t usually start a sentence with because.)
• I was feeling tired, so I went home early. (This is very common in spoken English.)
• The reason I went home early was that I was feeling tired.
• We can also use because of with a different construction. Compare:
• They go there because the weather is wonderful. (because + noun + verb)
• They go there because of the wonderful weather. (because of + (adjective) + noun)
• Due to means the same as because of, and is often used to explain the reason for a problem.
• The plane was late due to bad weather. (Due to is often used after the verb be.)

B. Purpose

• A purpose is an intention or reason for doing something.
• The purpose of the meeting is to plan next year’s timetable. [the reason for the meeting]
• We often introduce a purpose using so (that) or (in order) to :
• I bought this book so (that) I could improve my English.
• They went home early (in order) to watch the match on television.
• We moved house so (that ) we could send our children to this school.
• She went into town (in order) to do some shopping.

C. Result

• These link words/phrases are used when one thing happens because another thing has
• happened. Therefore and as a result are more formal than so , and less common in spoken English.
• I left my ticket at home, so I had to buy another one.
• They’ve got more money, and therefore they can afford to buy the best football players.
• I forgot to send the email. As a result , no one knew about the meeting.

D. Conditions

• We sometimes use whether [if] when we are not sure about something.
• I didn’t buy it because I wasn’t sure whether you’d like it.
• I spoke to the others, but I don’t know whether they’re coming.
• We’ll be late unless we leave now. [if we don’t leave now]
• Unless the weather improves [if the weather doesn’t improve], we won’t be able to go.
• I have to go now, otherwise [because if I don’t] I’ll miss the last bus.
• You’ll have to turn up the music, otherwise [because if you don’t] they won’t be able to hear it.
• You can borrow it as long as you bring it back by Thursday. [but you must bring it back]
• You can wear what you like as long as you look quite smart. [but you must look quite smart]
• I’m taking my umbrella in case it rains. [I’m doing A because B might happen later.]
• Take some money in case you need to get a taxi.