抛物线y=x24的焦点坐标是（） A．（0，116） B．（116，0） C．（1，_爱下问搜题

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问题选择题

抛物线y=

x2

4

的焦点坐标是（　　）

A．（0，

1

16

）

B．（

1

16

，0）

C．（1，0）

D．（0，1）

答案

抛物线y=

x2

4

即x²=4y，p=2，开口向上，

故焦点为（0，1 ），

故选D．

完形填空

Homework is work, not play. In contrast to what some might hope, students 55 finish their homework exclaiming that they had great fun. Nor is homework an activity that students choose to undertake. It is 56 by a teacher for students to complete on the teacher’s schedule, with the teacher’s requirements in mind． So to have the fight 57 Will be of great help. Homework means business and the student should expect to work on it seriously. As in the work place, careless efforts and lack of self-discipline are likely to make the 58 impression.
Teachers assign homework for 59 purposes. In some cases, teachers seek to review and solidify material being covered in class; homework is also designed to 60 student learning beyond class lessons. As students mature, teachers often assign homework nightly in several subjects. Homework is also used to prepare students to handle new work, 61 in the ease of summer reading. Increasingly, school reforms call for homework to take the form of course projects, thus increasing its 62 to “real-life” job-related activity.
Like jobs, homework can be appealing when its resources are well managed. Resources 63 sources of information—textbooks, of course, and increasingly, the Internet—but they also include a quiet space to work, materials and equipment such as calculators, paper or a computer, and others who cohabit (共面存在) in the homework environment. The external (外部的) resources needed for homework can be viewed as a kind of 64 . office for the child with features like those needed in the workplace.

单项选择题

光面爆破中，影响爆破效果最重要的爆破参数是（）。

A.掏槽深度

B.装药量的多少

C.周边眼的参数