In Chinese families, people won't start dinner ___________the elders take their seats.( )
A.afterB.whenC.becauseD.until
Getting enough sleep is good for _______ health _______ study.
— Hey, boy. You can’t cross the street now. You have to wait _______ the traffic lights turn green. — Oh, sorry and thank you.
Mom was cooking ________ Dad was reading newspapers.
It’s late. David washes his face _______ goes to bed.
()—Do you believe that paper is made ________ wood? —Yes, I do. And you can see that books are made ________ paper.