问题 单项选择题

过点A(1,4),且横纵截距的绝对值相等的直线共有().

A.1条

B.2条

C.3条

D.4条

答案

参考答案:C

解析:

设方程为y=kx+b

当截距不为零时(直线不过原点),即b不为0

当x为0时,y等于b,所以方程过(0,b),即方程在y轴上的截距是b的绝对值;

当y为0时,x等于,所以方程过即方程在x轴上的截距是的绝对值.

由题意得两截距相等得出

得k=1或-1

当k=1时,直线y=x+b把(1,4)代入得y=x+3

当k=-1时,直线y=-x+b把(1,4)代入得y=-x+5

当截距为零时(直线过原点),即b为0

直线方程为y=kx把(1,4)代入得k=4,y=4x

所以当截距不为零时y=x+3或y=-x+5

当截距为零时y=4x. 故选C.

选择题
阅读理解

阅读理解。

     You can love them or hate them, but no matter which tourist destination you visit, chances are you'll

see someone with their head buried in a Lonely Planet guidebook.

     Lonely Planet is one of the world's largest travel guide brands, publishing more than 500 different

guides in eight languages. The popular brand also produces television shows, websites and podcasts (播客)

all devoted to travel.

     Some people praise Lonely Planet books because they make traveling easy and affordable. They also save

time and make sure you don't miss the best things.

     They also provide the reviews of hostels (旅店), hotels, restaurants and ticket information about your

destination.

     This can be great if you're a nervous traveler, or if you haven't traveled hy yourself before. If you're in

a country where you don't speak the language, sometimes there's nothing better than getting into a taxi and

opening up a guidebook. You simply point to a map that directs the taxi driver to a hostel that's cheap and

clean, with friendly staff and cold beer.

     But others criticize Lonely Planet and other travel guide publishers like them. They say guidebooks take

the fun and spontaneity (自发性) out of traveling, and that part of the enjoyment of travel comes from the

fact that anything can happen. They also regret that if you follow a guidebook, you'll end up doing the same

thing and having the same experience as everyone else. You might end up seeing the same group of people

over and over, because everyone is reading the same book and following the same route.

     Another criticism of travel guides is that they have a large impact on local communities. For cxample,

some locals devote their lives to behaving in ways that attract tourists. They pretend to live a traditional

lifestyle, wear traditional clothes and live in traditional houses in order to attract the tourist dollar.

1. The Lonely Planet guidebook can bring you the following advantages EXCEPT that _____. [ ]

A. you can speak a foreign language when opening a guidebook

B. you can easily find a nice place to stay in a strange city

C. it provides lots of useful information about your destination

D. it can help you save time and money when traveling

2. People criticize the guidebook because _____. [ ]

A. it is not as useful as most travelers expect

B. tourist destinations will be crowded if everyone follows the same route

C. travelers may not get the chance to have unexpected adventures

D. local people keep modern lifestyles under its influence

3. What do we know about the Lonely Planet guidebook from the text? [ ]

A. It's a world-famous brand only producing guidebooks for travelers.

B. It's very useful to a person who's nervous about touring an unfamiliar place.

C. It's very u.seful to a tourist who likes to repeat others' experiences.

D. It is loved by all travelers because of the convenience it brings to travelers.

4. Which of the following best shows the structure of the text? (①-⑦ stand for Paragraph l- Paragraph 7) [ ]

A.  B.

C.  D.