[解析]
W:What are you guys doing?
M:Can't you see?We're making paper airplanes?
W:Yeah,I see that.But what are you doing with them?
M:We're flying them,of course.
W:Out of the window.
M:Yeah
W:That isn't right.You shouldn't throw paper out of the window.It'll land on the street and someone will have to pick it up.You're just making the street dirtier than it already is.
M:Now we aren't.First of all,we're not throwing the airplanes out.We're making them fly.And Second,most of our planes aren't going on the street.
W:Where are they going?
M:See that building across the street from us,We're sending them onto the roof of that building.We've already gotten more than 50 on there.
W:You're going to get in trouble.
M:Only if you tell mom and dad.