A.You're welcome.
B.Never mind.
C.Have a great day!
D.It's very kind of you to say so.

A.Let's drop it.
B.Why not?
C.No doubt about it.
D.Let me think about that and get back to you.

A.It is necessary for teens to join in sports and positive social activities.
B.Lack of adequate sleep puts teens at risk of performing poorly at school
C.Modern technology has something to do with teens' sleep problems.
D.Teens' sleep is linked to their relationship with people around them.

A.The harder
B.Hardest
C.Harder
D.The hardest

A.gave
B.gives
C.was giving
D.was given

A.does it
B.doesn't it
C.isn't it
D.is it

A.does it
B.doesn't it
C.isn't it
D.is it

A.A panel
B.uninterested judges
C.contestants
D.judged

A.woke up late
B.get much sleep
C.have been worrying
D.all night

A.he thought
B.ahead of
C.Some
D.because