BOOMbox爆炸机测量井口显示“Geo>800”时表示（）。A、检波器线缆短路 B、

用万用表不同欧姆档测量二极管正向电阻时，会观察到其测得的阻值不同，其根本原因是______。

A．万用表不同的欧姆档有不同的阻值
B．二极管有非线性的特性
C．二极管的质量差
D．以上都不对

下面文中共有10处语言错误，错误涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线(\)划掉。

修改：在错的词下划一横线，并在其下面写出修改后的词。

注意：1. 每处错误及其修改均仅限一词；

2. 只允许修改10处，多者（从第11处起）不计分。

It seems that there are a larger number of beggar in the

 streets than there used to be. I don’t know how we should help

 it or not. Once I gave some money to a beggar who looks

 poor. However, minutes later, I saw him bought some

cigarettes. It really shocked at me. In my opinion, anyone who

work hard can make a living. I’m afraid that giving them

money isn’t best way to help them. Maybe the government

can take some action to helping them. Anyway, if they

 want to live a better living, they should learn to depend

 on themselves.

下列实验操作正确的是[ ]

A．

B．

C．

D．

下列鱼类中鳃裂腹位的是（）。

A．黑线银鲛

B．赤魟

C．鲸鲨

D．食人鲨

U480（风机盘管调节开关）定货后是否已带边框？如果想带彩色边框应如何订货？