问题 问答题 简答题

为什么NS开关电子式控制单元4P3t、4P4t的订货号是一样的而热磁脱扣器是不一样的?

答案

参考答案:

电子式控制单元可通过旋钮调节中性线的保护,而热磁脱扣器需要通过选择合适的控制单元来实现中性线的保护。

阅读理解

Going to school from 8 am until 5 pm may sound terrible,but Sydney Shaw,a seventh grader at the Alain Locke Charter Academy on Chicago's West Side,has come to like it—as well as the extra 20 or so days that she's in class every year.“I'm sure every kid at this school says bad things about the schedule sometimes,”says Sydney, who was at school on Columbus Day, when most Chicago schools had a holiday.“But we all know it's for our benefit.”

Finding ways to give kids more classroom time,through longer hours,a longer school year,or both,is getting more attention.“If you want to look at schools where the achievement gap is narrowing, they're saying they couldn't do it without the added time,”says Jennifer Davis.“Even when you get good teachers into schools,you also need more time.”

According to studies, low-income students fall back more than two months in their reading skills over summer vacations.“It's over the summer months that poor kids fall behind,”says Karl Alexander,a sociologist.“If you have parents who themselves didn't succeed at school and aren't highly educated,kids aren't going to get those skills at home.”

Schools are asked to take a full year to plan how to best use the extra time—a process involving teachers,principals,students and parents.They are given outside support to help them base their plans on the best available analyses of student needs.It's still early,but officials are already seeing stronger test scores and a narrowing achievement gap.

But some critics are worried.“We risk producing something that's very expensive and time-consuming, and that will give educators a lot of trouble,”says Frederick Hess.“Before we spend all that extra money,I'd much rather see if we can figure out how to get 50 percent more instructional time out of the current school day.”

小题1:From the first paragraph,we learn that      

A.the longer schedule is harmful to kid's health

B.all Chicago students had a holiday on Columbus Day

C.Sydney Shaw supports the added time

D.few kids are bored with the lack of holidays小题2:Low-income students fall behind in summer because      

A.no good teachers are willing to teach them

B.they can't get help from their parents

C.their parents are unwilling to hire private teachers

D.they themselves have no desire to learn小题3:Some people are worried about adding school hours mainly because      

A.it will have a bad effect on the kids’ futures

B.the current school day has been too busy

C.no one supports the idea

D.it will be costly and time-consuming小题4:The text is mainly about      

A.whether a longer school day will help narrow the achievement gap

B.how students have benefited from additional school hours

C.why the achievement gap among students needs to be narrowed

D.what causes the achievement gap among students

填空题