哪句才對?謝謝!!!!!

C. Would you like to have some more soup before the main course.

main course = 主菜 <-----------CORRECT!
main cause = 主要的起因 ( How could this be correct?) @_________________@

C. Would you like to have some more soup before the main course?
( some more soup = 多 d soup )
A. Would you like to have a soup before the main course?
This is correct too. " soup" is liquid. You may think it is uncountable, but it is not that.
In oral English, we say " a coke, a coffee, a soup,etc" too.
To have a soup = doesn't mean to have more soup ( just a soup)
_______________________________
A and C are both correct! ( If you mean " a soup" use "A"
and if you mean " some more soup", use" C" then.)

B is wrong! ( IT IS " BEFORE THE MAIN COURSE", not main cause.)
另外, 想問蝴蝶魚是鹹水魚定你淡水魚?
Ans 鹹水魚
http://www2.hkedcity.net/sch_files/a/b79/b79-pwy/public_html/pp3.htm

A. Would you like to have a soup before the main course. 正確
圖片參考：http://tw.yimg.com/i/tw/ugc/rte/smiley_35.gif

B Would you like to have some more soup before the main cause.亦正確, 但意思不同. B句意即你己飲了(一碗)湯, 只是問你要不要加一點? (再來多一碗湯?)

B 一定錯...因為個CASUE 字.....

我覺得A 先對...因為外國人通常都會飲湯先...之後MAIN COURSE...所以問你飲唔飲湯好正常

SO..A is correct

I see no difference between options B and C ??

Neither are correct. You dont need "more". It's in a meal setting, then "main" is already understood. So

Would you like to have some soup before the/your main?

If the person is having soup, then it would have been
"Would you like a refill/topping up of your soup before your main?"

Would you like to have some more soup before the main course.

蝴蝶魚是鹹水魚,

蝴蝶魚聚居於珊瑚礁。

此生境是牠們的庇護場所及尋找食物的地方。

牠們靠捕食珊瑚或其他居住在珊瑚上的海洋生物維生。

B
Would you like to have some more soup before the main cause.
因為西式禮儀係會咁問隨

C. Would you like to have some more soup before the main course.
this is the correct one.