增加：在缺词处加一个漏字符号(Λ)，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。

Dear Joy,

    How are you doing? Here is an exciting news for you. There will be an invention competition in our school in the 20th of October. However, there is a rule the participants shall be in a group. But I'd like to invite you to be my partners.

    I know that you have been longed to design a tiny cooler that people can wear around the wrist. I think it will be a wonderfully idea for the competition. We can make a small air conditioner to controlling the temperature of the wearer.

    How do you think of my suggestion? Looking forward to you reply.

小明利用热敏电阻设计了一个“过热自动报警电路”，如图甲所示．将热敏电阻R安装在需要探测温度的地方，当环境温度正常时，继电器的上触点接触，下触点分离，指示灯亮；当环境温度超过某一值时，继电器的下触点接触，上触点分离，警铃响．图甲中继电器的供电电压U₁=3V，继电器线圈用漆包线绕成，其电阻R₀为30Ω．当线圈中的电流大于等于50mA时，继电器的衔铁将被吸合，警铃响．图乙是热敏电阻的阻值随温度变化的图象．

（1）由图乙可知，当环境温度为40℃时，热敏电阻阻值为____ Ω．当环境温度升高时，热敏电阻阻值将____ ，继电器的磁性将____ （均选填“增大”、“减小”或“不变”）．

（2）图甲中警铃的接线柱C应与接线柱____ 相连，指示灯的接线柱D应与接线柱____ 相连（均选填“A”或“B”）．

（3）图甲中线圈下端P的磁极是____ 极（选填“N”或“S”）．

温州雁荡山被联合国教科文组织评为“世界地质公园”。雁荡山的岩石主要以火山活动形成的岩浆岩为主。火山活动是(　　)