题干

某科学兴趣小组为了研究杏仁对昆虫的毒害作用,做了如下实验:

取三个相同的透明容器标为A、B、C,在A中加入少量的水和一定量的碎杏仁,在B中加入与A等量的碎杏仁,在C中加入与A等量的水。拧紧瓶盖,静置2小时,然后打开开瓶盖,在各容器铁丝网上分别放蚱蜢10只,再拧紧瓶盖(如上图),观察并记录蚱蜢状态如下表:

​ 

上一题 下一题 0.0难度 选择题 更新时间:2020-01-29 11:21:32

答案(点此获取答案解析)

同类题4

根据短文内容,选择正确答案。

                                                                                               C

    As you touch people and objects throughout the day, there are germs(细菌) on your hands. In turn, you can make yourself ill with these germs by touching your eyes, nose or mouth. Although it's impossible to keep your hands germ-free, washing your hands is good for you. It limits the chance of getting sick and is one of the best ways to avoid(避免) getting sick and spreading illness. Staying healthy can make you feel happier.

    Hand washing requires only soap and water, but do you really know when and how to wash your hands? The following information may be useful for you.

    When to wash your hands

    Always wash your hands before:

    ▲Preparing food

    ▲Eating

    ▲Giving medicine

    ▲Touching a sick or injured person Always wash your hands after:

    ▲Preparing food

    ▲Using the toilet

    ▲Touching an animal or animal toys or waste

    ▲Touching a sick or injured person

    Of course, it's also important to wash your hands whenever they look dirty.

    How to wash your hands

    It's generally best to wash your hands with soap and water. Follow these simple steps:

    ▲Wet your hands with running water.

    ▲Use soap.

    ▲Wash your hands for at least 20 seconds. Remember to wash the hands carefully, including the backs of your hands, wrists, fingers and fingernails.

    ▲Dry your hands with a clean towel.