试题与答案

目前可以作为用户接入网的主要有3类:Ⅰ.邮电通信网 Ⅱ.计算机网络 Ⅲ.局域网

题型:单项选择题

题目:

目前可以作为用户接入网的主要有3类:Ⅰ.邮电通信网 Ⅱ.计算机网络 Ⅲ.局域网 Ⅳ.广播电视网以下哪一个答案是正确的______。

A.Ⅰ、Ⅱ

B.Ⅰ、Ⅱ和Ⅲ

C.Ⅰ、Ⅱ和Ⅳ

D.Ⅲ、Ⅳ

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0603/ffc8c8a9f49bfe404405031e9964cd00.html

下面是错误答案,用来干扰机器的。

参考答案:A, B, C, D

试题推荐
题型:问答题


阅读以下说明和C语言代码,回答问题1至问题4,将解答填入对应栏内。
【说明】
在嵌入式操作系统设备管理的实现上,常使用到C语言的函数指针变量,由统一的管理函数调用不同的设备驱动程序。下面的一段C语言代码是驱动管理程序 manage_device调用4个不同设备驱动程序,但没有用到函数指针变量。
【C语言代码】
/*变量与类型说明*/
#include "stdio.h"
#include "stdlib.h"
extern int sys_status;
extern int Dev_drv1(int arg1, int arg2);
extern int Dev_drv2(int arg1, int arg2);
extern int Dev_drv3(int arg1, int arg2);
extern int Dev_drv4(int arg1, iht arg2);
#define NOERROR 0

type struct {
int _fd;
} TYP_DEV_TAB;
TYP DEV_TAB dev_tab[50]= {101,99, 80, 120,};

/*程序代码*/
void manage_device(int devid, int arg1, int arg2)
{ int place ;
int ret;
for(place=0 ; place<50 ; place++)
if dev_tab [place]. fd == devid) break;
if(place>=50)
printf(" NO DEVICE fd = %d\n ",devid);
switch(dev_tab [place]._fd) {
case 80:
ret = Dev_drv3(int arg1,int arg2);
break;
case 99:
ret = Dev_drv2(int arg1,int arg2);
break;
case 101:
ret = Dev_drv1(int arg1,int arg2);
break;
case 120:
ret = Dev_drv4(int arg1,int arg2);
break;
}
if (ret!=NOERROR)
printf(" DEVICE %d error!\n ", devid);
}

int Dev_drv1(int arg1,int arg2)
{
/*局部变量声明,略*/
/*驱动程序代码,略*/
}

int Dev_drv2(int arg1,int arg2)
{
/*局部变量声明,略*/
/*驱动程序代码,略*/
}

int Dev_drv3(int arg1,int arg2)
{
/*局部变量声明,略*/
/*驱动程序代码,略*/
}

int Dev_drv4(int arg1,int arg2)
{
/*局部变量声明,略*/
/*驱动程序代码,略*/

【问题2】
在C语言程序中,常在某些变量的说明前加extem,如本题在变量说明中的第一条加extem int sys_stams;请说明加extem与不加extem的区别,在进行编译时会有什么样的不同处理

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题型:阅读理解
Below are some smart ways to stay healthy suggested by some American experts.
Drink More Coffee
When was the last time you heard a doctor use the word miracle? Well, wake up and smell the coffee: “It’s amazing,” says liver specialist Sanjiv Chopra, MD, professor of medicine at Harvard Medical School. “Coffee is truly a lifesaving miracle drug.”
Though he says it’s still a “scientific mystery” how a simple cup of coffee works its wonders in the body, large epidemiological studies have repeatedly proved its astonishing benefits.
“Drink it black, or at most put a little skim milk in it” to minimize calories, Dr. Chopra recommends. He drinks at least four cups a day himself, though most people should limit themselves to two. And no, he jokes, “I’m not sponsored by Starbucks.”
Take a Walk for Your Memory
Aerobic (有氧运动的) exercise is good for your body, great for your mind, according to the latest research from brain-fitness pioneer Arthur Kramer. Every year, an area called the hippocampus, which is key to memory, shrinks by about 1 to 2 percent, increasing the risk of dementia (脑衰) as the years roll by. However, Kramer’s new investigations reveal that the hippocampi of adults who walked briskly for about 45 minutes three times a week grew by about 2 percent over the course of a year, preventing age-related shrinking.
It’s never too late to start exercising, Kramer says; volunteers in his research were between 55 and 80 years old and hadn’t exercised at all. And it doesn’t need to be backbreaking. “Anything that raises your heart rate seems to work,” he says. “Walking is fine. Just find something you like and do it.”
Early to Bed, Early to Eat
“Being a night owl might increase your waistline,” says sleep expert Michael Breus, PhD. People who stay up late and sleep late tend to eat more fast food and consume more of their calories after 8 p.m. than do normal sleepers.
“One of the easiest things that anyone on a diet can do to improve her results is go to bed and wake up at the same times every day,” Breus says. “This way, your body knows when to sleep and is much more efficient. Organize your eating, too, by trying to eat meals at the same times every day. Avoid eating after 8 p.m., and don’t miss morning meals by sleeping in.”
Use the 20-Second Rule
What’s the difference between having a goal and actually accomplishing it? Just 20 seconds, says positive-psychology specialist Shawn Achor. Researchers have learned that if we can cut 20 seconds off the startup time required for a task, we’re much more likely to follow through. So, for example, if you want to work out in the morning, place your shoes and exercise clothes next to your bed the night before. If you want to praise people more, put thank-you notes and a pen on your desk.
Imagine the Worst to Feel Better
Don’t count your blessings; subtract (扣除) them. “Consciously spend a few minutes imagining what your life would be like without the good things,” says Timothy Wilson, a psychologist at the University of Virginia. You’ll experience stronger feelings of love, gratitude, and happiness when you think about what life would be like without the people and things you love. “And they’ll seem surprising and special again,” he adds.
小题1: According to Sanjiv Chopra, most people should not drink more than ______ cups of coffee a day.
A.twoB.threeC.fourD.six
小题2:Which of the following may help people on a diet to improve their results?
A.Raising their heart rate.B.Taking a walk for their memory.
C.Eating at fixed times.D.Sleeping in every morning.
小题3:According to Shawn Achor, if people place their shoes and exercise clothes next to their bed at bedtime, they’re more likely to ______ the next morning.
A.do exerciseB.set a goal
C.cut 20 seconds offD.sleep 20 minutes more
小题4: Why should people spend a little time imagining their life without good things?
A.To experience surprise.B.To feel better.
C.To consider their own blessings.D.To prepare for the worst.
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