内痔的早期临床表现为（）。 A.黏液血便 B.便后脱垂 C.无痛性、间歇性便后出血

阅读短文，选择正确答案。

    If there is time for questions or discussion at the end of a class, take the chance to ask for further explanation

of anything that was not immediately clear. You are unlikely to be the only one who does not understand. So

our questions will help others and will encourage them to ask questions, and you should learn from all the

teacher's replies.

    Questions not only help students to learn but also show interest in the subject, and this makes the teacher's

work more useful. Besides, questions should help the teacher first to recognize things that students find difficult

and then to give better lessons. More questions will come to mind during your further studies. Try to find the

answers before the next class. This will help you to learn.

1. The writer of this passage advises us _____. [ ]

A. to ask for further explanation of everything we learn

B. to ask questions at the end of a class

C. to help others by asking the teacher questions

D. to encourage the teacher to give better lessons

2. According to the passage, you ask questions in order to ____. [ ]

A. make your teacher recognize you

B. encourage your school friends to learn better

C. make yourself and your classmates learn better

D. satisfy your teacher

3. According to the passage, questions are helpful _____. [ ]

A. either to the slow students or to the bright students

B. to both the teachers and the students

C. neither to the teachers nor to the students

D. especially to some teachers

如图，L型弯管有一柔软但不可被压缩（或拉伸）的长度为l的物体，其截面直径比L型弯管径略小（管径与物体的长度相比可以忽略），该物体可在L型弯管中移动，且物体在弯角处移动时无能量损失．已知L型弯管的竖直部分光滑，水平部分与物体间的动摩擦因数为μ（μ＞1），且最大静摩擦力等于滑动摩擦力．现让物体在竖直外力作用下保持静止，设物体的上端离水平管的竖直距离为x．

（1）若物体的一部分在水平管中，撤去外力后，物体能在原位置保持静止，求此情况下x的取值范围．

（2）若物体全部在竖直管中，撤去外力后，物体能全部进入水平管中，求此情况下x的取值范围．

（3）若x=2μl，求撤去外力后物体右端进入水平管的距离．

定义有5个整数型元素的数组，正确的语句是______。

A．Dim a(4)As Integer

B．Option Base 1：Dim a(5)

C．Dim a&(5)

D．Dime a(5)As Integer

重大事项停息后，案发机构如何处理？

矿井主要通风机的工作风量怎样测定？