⑴What did you buy?                          A. It's a pen.

⑵I bought you a pen.                         B. I bought a lot of things.

⑶Did you buy me a pencil?               C. I got a pen and a book.

⑷What is it?                                       D. No.

⑸What presents did you get?           E. Thank you.

    A rocket (火箭) looks like a big tube (管状物). It takes astronauts (宇航员) and spacecrafts (航天器), such as satellites (人造卫星) and space shuttles (航天飞机) up into space. They travel in the rocket' s nose (突出部位). A rocket is much faster and more powerful (强有力的) than any plane. A rocket can only go into space one time.

    Rockets fly straight up and pass through the atmosphere (大气层) into space. How do rockets get their power? There are liquid fuels (液体燃料) in the bases (底部) of rockets. When they burn (燃烧) they make many hot gases (气体). The gases shoot out (喷射出) of the backs of the rockets and push them off the ground.