This week's question comes from Lok and they want to know what the word cos means.

Quite simply it is a short form of the word because. Native English speakers often shorten this word, no doubt because it's easier to do that. Words are joined together or shortened a lot when native speakers talk so it's good to be able to look out for these things to help understand English better.

	Everyone uses cos in English, even the rich and famous!

So basically any time you want to say because in a sentence, you can just say cos (which is sometimes spelt 'cause).

You might hear this more in informal situations like a group of friends talking together. However, you find that British people are often quite informal in formal situations, so you may hear cos used in more formal settings.

Listen to our programme which explains a lot more about this word. You'll find out that even famous people use cos a lot!

Thank you Lok for your question. If you have a question about the English language, send us an email at questions.chinaelt@bbc.co.uk.

Glossary 詞匯

a short form

縮寫

native English speakers

英語為母語的人

shorten

縮短

no doubt

毋庸置疑

to look out for

關注

a sentence

一句話

informal

非正式的/隨便的

formal settings

正式場合