1.15 BECAUSE THEN, SO

 Because is a subordinating conjunction, which means that it connects a subordinate clause to an independent clause; good style dictates that there should be no comma between these two clauses. An exception can and should be made when the lack of a comma would cause ambiguity.

Grammatically speaking, then is used as an adverb or adjective, while than is used as a conjunction or preposition. Perhaps the most common way the two words are confused is when then is used when it should be than, but doing the reverse is also a common mistake.

• Because is used to give reasons.

• She doesn’t go to school because she’s sick.
• Because it rains, I wear a raincoat.
• Kate was happy because she won the competition.

We use so as a subordinating conjunction to introduce clauses of result or decision: I got here late. It was a long journey, so I'm really tired now. You are right, of course, so I think we will accept what the bank offers. It's much cheaper with that airline, isn't it, so I'll get all the tickets for us with them.

Then is also used to indicate what happens or happened next, or what should be done next, as in the following sentences:

• First I went to the store, and then I got gas.
• Finish your homework, and then you can watch TV.
• Turn right at the next street, then turn left at the light.

• So is used to link between cause/ reason and results

• He’s hungry so he gets some food.
• The weather isn’t very nice so we don’t go camping.
• He lost the key so he couldn’t get into his room.

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