短文改错

文中共有10处语言错误，每句中最多有两处。每处错误仅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（∧），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，并在该词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。

    Nowadays more and more people who lives in cities like to keep dogs as pets. Some of my friend believe people can get comfort and develop their patient and love by keeping dogs as pets. Personally, I do not really have interest to dogs, and sometimes I do hate some dog owners. They can be so annoyed. They talk about their dogs as if they are actually their little babies. Some dogs make too much noise at night, that makes it hard for people living nearby fall asleep. Besides, not all dog owners think of others while they are walking their dogs. As really annoys me, though, is the way they let their dogs get out of the control.

①前一个“必须”强调受教育是适龄公民的义务

②义务教育是适龄公民应该享有的权利，适龄公民可以行使也可以放弃

③我们中学生应该珍惜受教育的权利，自觉履行受教育的义务

④后一个“必须”强调受教育是适龄公民享的权利

如图所示电路，电源电压恒定不变．当S₁闭合、S₂断开时，电压表的示数为3V；当S₁断开、S₂闭合时，电压表的示数为9V，则此时I₁：I₂=____ ；  R₁：R₂=____ 。