订货提前期包含哪些时间？（） A.订单准备时间 B.排队时间 C.加工时间 D.搬运

一个小球沿斜面向下运动，用每隔（1/10）s曝光一次的频闪相机拍摄不同时刻小球位置的照片，如图所示。

即照片上出现的相邻两个小球的像之间的时间间隔为（1/10）s，测得小球在几个连续相等时间内位移数据见下表：

（1）小球在相邻的相等时间内的位移差____________（填“相等”或“不相等”），小球运动的性质属____________直线运动。

（2）甲、乙两同学计算小球加速度的方法如下：

甲同学：a₁＝(x₂－x₁)/T²，a₂＝(x₃－x₂)/T²， a₃＝(x₄－x₃)/T²，＝(a₁＋a₂＋a₃)/3；

乙同学：a₁＝(x₃－x₁)/(2T²)，a₂＝(x₄－x₂)/(2T²)，＝(a₁＋a₂)/2。

你认为甲、乙两位同学中计算方法更准确的是____________，加速度值为____________。

决策树的分析程序包括：①剪枝决策②计算期望值③绘制树形图。排序正确的是（）。

A.①②③

B.③②①

C.③①②

D.①③②

So long as teachers fail to distinguish(differ) between teaching and learning, they will continue to undertake to do for children that which only children can do for themselves. Teaching children to read is not passing reading on to them. It is certainly not endless hours spent in activities about reading. Douglas insists that "reading cannot be taught directly and schools should stop trying to do the impossible".

Teaching and learning are two entirely different processes. They differ in kind and function. The function of teaching is to create the conditions and the climate that will make it possible for children to plan cleverly the most efficient system for teaching themselves to read. Teaching is also a public activity: It can be seen and observed.

Learning to read involves all that each individual does to understand the world of printed language. Almost all of it is private, for learning is an occupation of the mind, and that process is not open to public scrutiny.

If teacher and learner roles are not interchangeable, what then can be done through teaching that will aid the child in the long search for knowledge Smith has one principle rule for all teaching instructions. "Make learning to read easy, which means making reading a meaningful, enjoyable and frequent experience for children. "

When the roles of teacher and learner are seen for what they are, and when both teacher and learner fulfill them properly, then much of the pressure and feeling of failure for both is got rid of. Learning to read is made easier when teachers create an environment where children are given the chance to solve the problem of learning to read by learning.

The teaching of reading will be successful if（）

A. teachers can make their teaching activities observable

B. teachers can teach their students how to read

C. teachers can improve conditions at school for the students

D. teachers can enable students to develop their own way of reading

鲍特菌引起百日咳的临床治疗首选用药是（）

A.红霉素类

B.复方磺胺

C.氨曲南

D.青霉素

E.咳喘宁

带阻尼孔的负重选型非对称的斜盘式柱塞液压泵如果反转，将会（）。

A.发生困油现象

B.电机过载

C.产生噪音和振动

D.A＋B＋C