选择恰当的关联词填空。

因为    如果……就……    无论……都……    虽然……但是……

①我们____不努力学***____没有文化知识。

②____它是母鸡。

③在夜间若有什么动静，它便放声啼叫，顶尖锐，顶凄惨，____多么贪睡的人____得起来看看，是不是有了黄鼠狼。

   We usually have three meals. We have breakfast, lunch and supper. We often have more time for lunch and supper, and we eat a big lunch or supper. But a good breakfast is very important (重要的). It's easy for you to understand it. You don’t eat anything for about twelve hours from the last (上次) supper.
   One good breakfast should be rice or bread, an egg and milk. On a cold morning a cup of hot drink is necessary (必需的). Get up a little early and you can have enough time to eat breakfast. A good breakfast helps you to study well. It helps you to work well and play happily. You will be fun for a day after you enjoy a good breakfast.

（1）条形磁铁磁性减弱了，小红采用如图1所示的方法增强它的磁性，请你在图中标出电源的“+”、“﹣”极和小磁针的N极．

（2）如图2所示，S₁是光控开关，夜晚自动闭合，白天断开；S₂是声控开关，有声音时自动闭合，安静时断开．请把图连接成声光控楼道节能照明电路．