题干

滑雪是人们在冬季喜爱的运动,如图所示,为什么人们在滑雪时要脚穿又长又宽的滑雪板?

上一题 下一题 0.0难度 选择题 更新时间:2019-07-04 05:43:35

答案(点此获取答案解析)

人对雪地压力一定,穿上滑雪板,增大了雪地的受力面积,减小了人对雪地的压强.

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  Camping in your backyard is full of fun,whatever your age.It's great for keeping us relaxed.It offers chances to check the night sky and to be noisier than usual.It lets us have friends over to stay who might not fit inside the house! Follow these instructions and you'll have a night you'll never forget! 

  Put up your tent.

Depending on the number of family members and guests,you may need

 more than one tent.Tell your friends to bring their tents if needed.Follow the instructions or check out the articles on how to put up a tent on the Internet.

    Prepare your bedding.

    You'll want your guests to be able to relax in comfort.Put something soft to lie on on the floor:A blow-up air mattress or thick comforters may work well.Fill the tent with soft toys and blankets(毯子).Have lightweight sleeping bags or cotton blankets.They are especially important if you live where the night temperatures drop greatly.

    Prepare a seating area.

    If you have a picnic table,that would work best.If not,set up a few chairs and a small table to set out drinks and food.A simple choice is to lay out a blanket in the sun,so that your friends can eat and talk.Be sure the grass isn't wet!

    Make memories.

    Plan some activities.You're camping in the backyard,so it's time to make the most of being outdoors.

    Have a camera nearby to take silly photos of you,your family members,and your friends.Take one large group shot with everyone smiling and laughing.Be sure to make copies for everyone !