题干

 摘录某同学实验记录本中有关实验现象的记录,其中肯定有误的是(  )​


A:硫在氧气中燃烧,会发出明亮的蓝紫色火焰,产生有刺激性气味的气体

B:细铁丝在氧气中点燃时,剧烈燃烧,火星四射,生成黑色固体

C:点燃一氧化碳时,火焰呈蓝色,产物能使澄清石灰水变浑浊

D:在空气中打开盛浓盐酸的试剂瓶瓶塞,有刺激性气味,产生白烟

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答案(点此获取答案解析)

D

同类题3

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项,选项中有两项为多余选项。

How to Prepare for Guests

    Guests are people whom we welcome sincerely and we should make sure they feel comfortable like they are in their home. Sometimes we get enough time to make preparations for guests, but sometimes we don't. This article will be beneficial for both these kinds of people. ____

    Get a bedroom for your guests. It doesn't have to be complicated. Change bed covers, clean the bathroom and you can even add a nice scented(芬芳的) candle to spice things up. These are simple things you can do even if you are a very busy person. ____

    Know what your guests' favorite foods are so that you can make for them and serve. Don't forget to note down if they are allergic to any certain kind of food to save the embarrassment(难堪). If you are among one of those people who can hardly manage the time to cook for your guests then take them to the restaurants so that they can taste new foods or enjoy their favorite ones.

    Plan activities to have a good time with your guests. ____ If they come over the weekends then plan for some indoor activities to have fun. It's also a good way to remove your tiredness from your boring life.

    ____ It can happen that you may not be able to be with your guests for a certain amount of time while they are staying in your home. In that case you must declare it to them and may have someone else to accompany them while you are absent.

    When your guests say goodbye, give them something as a token(信物) of love to remember the days they stayed with you. ____

A. Declare your absence.

B. Allow them to come and go as they please.

C. Just bear in mind everything fresh and clean will do fine.

D. If they come during the vacation then you can plan for outdoor activities.

E. Here are some ways to help you to put away things well in a short amount of time.

F. Make your guests feel even more welcome by including them in activities such as outings, or movies.

G. It can be just a photo in a beautiful frame that will remind them of beautiful moments that they spent with you.