阅读下面短文，掌握大意，然后请从A、B、C、D四个选项中选出最佳选项。
When are you an adult?
When do you think you are an adult? Maybe different     have different ideas.
Now let's see what some American teenagers say.
Sam: In    idea, you are an adult at the      of 18. That's when you can vote(投票）. You can help to   who rules the whole country. That's also a grown-up does! My grandfather couldn't vote    he was 21. They changed it to 18 in 1971.
Jenny: I don't     it's hard to say. I can drive a car at 16, can't I? When you have a driver's license, you can     it to people to tell them your age for all kinds of things.      sixteen must be the age when you change from a       person to an adult. Because you can tell others you are not a        any more.
Suzie: Well, I think there is    wrong with American laws for when young people can     things. I can vote at 18 and drive at 16. So you would think that 18 is a grown-up,     16 isn't. But then I can't drink wine until I'm 21! If I'm     an adult at 18, how can people stop me from       a cup of beer in a bar?

A．teenagers B．adults C．drivers D．grandfathers

A．his B．my C．her D．your

A．age B．end C．front D．number

A．make B．keep C．teach D．choose

A．after B．until C．when D．if

A．hope B．want C．like D．think

A．show B．send C．ask D．pass

A．But B．And C．So D．Or

A．old B．young C．little D．tall

A．baby B．grown-up C．boy D．kid

A．anything B．everything C．something D．nothing

A．do B．buy C．like D．borrow

A．as if B．even though C．ever since D．above all

A．already B．still C．also D．yet

A．selling B．making C．drinking D．giving