一只重500N的箱子放在水平地面上，甲学生用100N的水平力将箱子水平移动10m，乙学生把这只箱子匀速提高2m，那么，他们做功的大小是(    )

    The Sea Life Centre is a Really Exciting Place
    Good morning, everyone.1 to the new Sea Life Centre at Plymouth.The Sea Life Centre is a really exciting place. There are so many things to2here and everything is enjoyable. It costs $3.76 for adults ,  $2 for children and 3 for over sixties and school groups. It's 4 from 9:00am to 4:30pm every day except 25^th and 26^th of December.Special 5include hourly feeding times for all the different animals and fish, and shows in the sea life theatre. 6  is always there to answer questions about what you've seen. 7 you are in a group of six or more people, we  8 give you a special guided tour of the centre. But you 9 to arrange(安排 ) this at the information desk when you 10.
    The latest attraction(吸引人的事) is a big 11 tunnel(隧道 )you can walk through. All around you, you will see fish swimming--- sometimes even over your head. You certainly have the 12view(景色 ) of the undersea world. Children 13 it and it's really amazing for adults, too.
    When you get 14, there is a relaxed family dining room serving food.That's all. For 15information, phone 091743-564219. Have a good time! Thank you.