加工一批零件,甲单独做6小时完成,乙单独做9小时完成,甲、乙合做______小时

题型:填空题

问题:

加工一批零件,甲单独做6小时完成,乙单独做9小时完成,甲、乙合做______小时可以完成.

考点:整数,小数,分数,百分数和比例的复合应用题
题型:填空题

根据你的生活经验和所学的化学知识判断,下列做法正确的是(    )

A.用食盐配制生理盐水

B.在食品袋里充入氧气延长食品的保质期

C.被蚊虫叮咬后,可涂一些含NH3·H2O的药水

D.用钢丝刷擦洗铝锅上的污垢

题型:填空题

肝脂肪变性时,肝细胞内可出现明显增多的脂滴,其成分主要是()

A.中性脂肪

B.脂褐素

C.胆固醇

D.脂蛋白

E.类脂质

题型:填空题
Kuss Middle School serves students in Fall River, Mass. , a former mill town that has struggled economically for decades. Students at Kuss have struggled, too, usually falling short of making the academic progress required under the No Child Left Behind law.
Then, last year, the school experimented with extending the school day. Teachers got paid at a higher hourly rate.
Students weren't thrilled at first with leaving school at 4:15 p.m. instead of at 2:20 p.m. But the added hours gave them more time for physical education and let them select special interest classes. By the end of the year, student scores had risen by enough to enable Kuss to make the progress required under the federal No Child Left Behind law.
The only surprise is that more districts haven't lengthened school schedules set decades ago to accommodate (适应) a farm economy rather the information economy of today.
School days
The USA ranks 36th of 40 industrialized nations in average weekly instructional time.
Selected countries:
1) Thailand--30.5 hours  2) Korea--30.3 hours  7) China--26.5 hours
14) France--24.6 hours  15 ) UK--24.6 hours
16) Mexico--24.2 hours  23 ) Japan--23.8 hours
26)Canada--23.6 hours  36)USA--22.2 hours  40)Brazil--19 hours
New research suggests the time is ready for a change:
Matched against 39 other developed countries, the United States is near the bottom in the rankings of average weekly instructional time in school.  Measured over 12 years, students in the top-scoring countries spend the equivalent of a full extra year in school.
US students perform poorly on math and science tests compared to their international peers, according to a US Education Department comparison released earlier this month. In math, American 15-year-old scored near the bottom among the study's 30 developed countries.
Most countries that boost the number of minutes spent on math instruction find pay offs in improved math scores, according to a study released this month by the Brookings Institution. Small in creases in the school day are more effective than a longer school year, the report concluded.
The most encouraging news about the benefits of extending the school day comes from Massachusetts, where an experiment with 10 schools, including Kuss, appears to be working. Those 10 schools lengthened their instructional days by 25% and boosted their state scores in math, English and science at all grades.
Perhaps the concept won't work everywhere. Certainly, it won't instantly be popular. But it's obvious that a problem exists or that adding class time seems to help.
小题1:What is the main idea of the above passage?
A.Experiments with extended school hours produce academic gains.
B.Kuss Middle School sets a good example for US education.
C.Academic progress has achieved under the No Child Left Behind law.
D.Information age calls for more instructional lime at all schools.
小题2:A longer school day is suggested for the following reasons except that _________.
A.students from many developed countries spend more time at school
B.American students do a bad job at science subjects
C.teachers are paid at a higher rate with time added
D.a longer school day works better than a longer school year
小题3:Which statement is true of Kuss Middle School?
A.Kuss Middle School lies in where a farm economy is changing to an information one.
B.Kuss Middle school has joined the federal "No Child Left Behind" progrann
C.Neither teachers nor students are happy with the longer school day.
D.Adding class time functions at Kuss Middle School.
小题4:The writer has expressed ____________.
A.a positive attitude towards adding school time
B.a negative attitude towards adding school time
C.a changing attitude towards adding school time
D.a right attitude towards adding school time
题型:填空题

秘密载体的寄递范围,分为省际寄递、省内寄递和________________寄递三种。

题型:填空题

根船舶开航前大副应做下列哪些准备工作?()

Ⅰ检查货运单证是否齐全

Ⅱ通知无关人员离船

Ⅲ核实船舶开航吃水,严防超载

Ⅳ检查二副是否按时改妥海图和资料

A.Ⅰ~Ⅳ

B.Ⅰ~Ⅲ

C.Ⅱ~Ⅲ

D.Ⅰ、Ⅲ、Ⅳ

更多题库