题干

(1)有位同学家中使用的燃料是天然气,为安全起见,计划在厨房安装天然气泄漏报警器.该同学认为报警器安装的位置应如下图所示:你认为这样安装是否合理____ ,请说明理由____ ;

(2)如果报警器显示有天然气泄漏,下列应急措施可行的有(填编号)____  .

A.检查并关闭气源阀门,防止气体进一步泄漏       

B.轻轻打开门窗通风

C.立即打开电动抽风机抽风,把泄漏出的天然气尽快排出室外.

上一题 下一题 0.0难度 选择题 更新时间:2018-09-05 09:08:53

答案(点此获取答案解析)

合理,因为天然气的密度比空气的小,AB

同类题4

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    Homework is a major part of going to school: It's your teachers' way of evaluating(评价) how much you understand of what's going on in class.____ Luckily, you can do a few things to make homework less work.

    Be sure you understand the homework.

    Write your homework down in your notebook or day planner if you need to.____It's much easier to take a minute to ask the teacher during or after class than to struggle to remember later that night!

    Use any extra time in school.

    Many schools have study halls that are specifically designed to allow students to study. It's tempting(诱惑) to hang out with friends during study periods or unstructured(松散的) time.____

    Take a break.

    ____ So take some breaks while doing your homework. Sitting for too long without stretching or relaxing will make you less productive than if you stop every so often. Taking a 15 minute break every hour is a good idea for most people.

    ____

    If you don't finish your homework during school, think about how much you have left and what else is going on that day, and then budget your time. Most high school students have between 1 and 3 hours of homework a night. If it's a heavy homework day and you've got an assignment in every subject, you'll need to devote more time to homework. It's a good idea to come up with some kind of homework schedule, especially if you are involved in sports or activities or have an after school job.

A. Make a homework schedule.

B. Settle down to do homework.

C. And it helps digest important concepts.

D. Most people's attention spans (跨度) aren't very long.

E. Don't be afraid to ask questions about what's unknown.

F. Once your homework is done, you can check over it if you have extra time.

G. But the more work you can get done in school, the less you'll have to do that night.