题干

根据等电子原理:由短周期元素组成的微粒,只要其原子数相同,各原子最外层电子数之和相同,可互称为等电子体,它们具有相似的结构特征.以下各组微粒结构不相似的是(  )

A:CO和N2

B:O3和NO2

C:CO2和N2O

D:N2H4和C2H4

上一题 下一题 0.0难度 选择题 更新时间:2019-12-22 11:45:17

答案(点此获取答案解析)

D

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根据短文内容回答问题

  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 !