电气化区段微机交流计数电码自动闭塞设备,发码器U3的6脚应为2kHz±0.5kHz方

题型:单项选择题

问题:

电气化区段微机交流计数电码自动闭塞设备,发码器U3的6脚应为2kHz±0.5kHz方波,幅值()。

A、不大于4V

B、不小于4V

C、不大于8V

D、不小于8V

考点:信号工考试中级信号工中级信号工题库
题型:单项选择题

All students need to have good study habits(习惯).When you have good study habits, you learn things quickly. You also remember them easily.

Do you like to study in the living room? This is not a good place because it is usually too noisy. You need to study in a quiet place, like your bedroom. A quiet place will help you only think about one thing.

When you study, don’t think about other things at the same time. Only think about your homework. If you do this, you will do your homework more quickly and you will make fewer mistakes.

Good study habits are very important. If you do not have them, try to learn them. If you are already good, try to make them better.

小题1:This passage(文章)tells about._______.

A.good study ways

B.good study habits

C.good study environment

D.the homework小题2: When do you remember things easily?_______.

A.When we study

B.When we learn things

C.When we need to have good study habits

D.When we have good study habits小题3: How do you learn things when you have good study habits?

A.All students need to have good study habits.

B.Do not think about other things.

C.We will learn thing quickly.,

D.Only think about our homework.小题4:You must only think about _______when you study.

A.good study habits

B.other things

C.your homework

D.mistakes小题5:If you do not have good study habits, you must _______.

A.try to learn them and have them

B.try to make them better

C.try to make fewer mistakes

D.try to do our homework quickly.

题型:单项选择题

已知氢氧化钡溶液和硫酸钠溶液反应生成硫酸钡和氢氧化钠.现实验室中有一包白色粉末,可能是碳酸钠,也可能是氧化钙或硫酸钠.为确定其组成,某同学设计了以下实验方案进行探究,请你按要求帮助完成探究活动.

(1)提出假设:假设①:白色粉末是碳酸钠假设②:白色粉末是氧化钙假设③:白色粉末是硫酸钠

(2)设计实验,通过实验分析进行判断并填空:

假设  设计的相关实验操作实验中观察到的现象假设是否成立
取一定量粉末加入稀盐酸    没有气体产生______
  ②  取一定量粉末溶于水溶液浑浊且温度升高______
取一定粉末溶于水,静置后取上层清液再加入氢氧

化钡溶液

没有沉淀产生______
(3)实验后思考:假定这包白色粉末是混有少量氧化钙的碳酸钠粉末,将混合物溶于水可观察到的现象是______.

题型:单项选择题

下面类中,有两个下拉列表,一个可以选择月份,一个可以选择2000--2009年之间的年份。
import javax.swing.*;
public class Expiration extends JFrame

JComboBox monthBox=new JComboBox();
JComboBox yearBox=new JComboBox();
public Expiration()

super("Expiration Date");
setSize(240,90);
setDefaultCloseOperation(JFrame.EXIT ON CLOSE);
JPanel pane=new JPanel();
JLabel exp=new JLabel("Expiration Date:");
for(int i=0;i<13;i++)

monthBox.addItem(" "+i);

for (int i=2000;i<2010;i++)

yearBox.addItem(" "+i);

pane.add(exp);
pane.add(monthBox)
【12】
setContentPane(pane);

public static void main(String[] arguments)

Expiration expiration=new Expiration();
expiration.show();


请在画线处填入正确的语句使得程序完整。

题型:单项选择题

关于居间人的权利义务,下列表述正确的是:

A.因居间人提供订立合同的媒介服务而促成合同成立的,由该合同的当事人平均负担居间人的报酬

B.居间人未促成合同成立的,不得要求支付报酬,且应当自行负担居间活动的费用

C.因居间人的故意或者重大过失损害委托人利益的,应当承担损害赔偿责任

D.居间人促成合同成立的,居间活动的费用由委托人负担

题型:单项选择题

纯苯与甲苯两相混合馏分常压沸程不应包括()℃。

A.74

B.84

C.109

更多题库