Hurry up ____ finish your soup!

My friend’s flight had taken off _________ I got to the airport to see him off.

 -- _____ classes are there in your school?   –Thirty. 

---Why does Maria look so tired?---She missed our school bus, ______she had to walk here all the way. 

_________many children like KFC, I think they’d better try not to eat it too often.