搜题请搜索小程序“爱下问搜题”
问题 选择题

斜率为-3，在x轴上的截距为2的直线的一般式方程是（　　）

A．3x+y+6=0

B．3x-y+2=0

C．3x+y-6=0

D．3x-y-2=0

答案

在x轴上的截距为2的直线经过点（2，0），

又斜率为-3，

点斜式可得直线的方程为：y-0=-3（x-2），

即 3x+y-6=0，

故选C．

单项选择题

慢性支气管炎并发阻塞性肺气肿病人的临床表现主要是在原有症状的基础上又出现( )。

A．经常发热
B．逐渐加重的呼吸困难
C．剧烈咳嗽
D．咳多量脓痰
E．反复发绀
查看答案
单项选择题

Melissa and LoveLetter made use of the trust that exists between friends orcolleagues．Imagine receiving an (71) from a friend who asks you to open it．This is whathappens with Melissa and several other similar email (72) ．Upon running，such wormsusually proceed to send themselves out to email addresses from the victim’s address book，previous emails，web pages (73) ．

A．cracker B．user C．customer D．client

As administrators seek to block dangerous email attachments through the recognition ofwell—known (74) ，virus writers use other extensions to circumvent such protection．Executable(.exe)files are renamed to．bat and．cmd plus a whole list of other extensions and wilt still runand successfully infect target users．
Frequently，hackers try to penetrate networks by sending an attachment that
looks like a flash movie，which，while displaying some cute animation，simultaneouslyruns commands in the background to steal your passwords and give the (75) access to yournetwork．
供选择答案：
查看答案