All the students were studying in class　　　 Tom;he was playing football on the playground.

You have failed two tests. You’d better start working harder, ____ you won’t pass the course.

I don’t know the reason        you were late for the meeting, but I’m sure someone will tell me        you don’t want to explain.

This is a process          happens when land becomes desert        people cut down trees and dig up grass. 

Mike resembles his mother in appearance _____ his personality follows his father's.