1 câu có "so": - I was sick, so I quit school.
2 câu có "because": -I like math because I like numbers.
                                - I like to paint because I paint beautifully.
3 câu có "although": -He drove really fast, although it was foggy.
                                - She is good at school, although her home is poor.
                                - He drove slowly, although there were no people on the street.

- Câu có "so"
+ I didn't like the book. The story was so stupid.
- Câu có "because"
+ I don't like her because she is mean and arrogant.
+ Her key was lost because her children had dropped it on the road.
- Câu có "although"
+ Although he has a bicycle, he goes to school by bus
+ Although it rained a lot, we enjoyed our holiday.
+ I didn't get the job although I had all the necessary qualifications

so:
1 - Today I overslept so I was late to study
( hôm nay tôi ngủ quên vì thế tôi đi học muộn)
because:
1 - Lan studied well because she studied hard
( Lan học giỏi vì cô ấy chăm học)
2 - I dont watch news because it is boring
( tôi không xem tin tức vì nó buồn chán)
Although
1 - Although BBC the Coast is a famous TV series I have never watched it
( Mặc dù BBC the Coast là một bộ phim truyền hình nổi tiếng nhưng tôi chưa bao giờ xem nó)
2 - Although job is hard, her salary is low
( Mặc dù công việc vất vả, lương của cô ấy lại thấp)
3 - Although it is quite late now, I am still studying English
( Mặc dù bây giờ đã khá muộn, tôi vẫn đang học tiếng anh)