雅典民主政治的实质是

在锥形瓶中加入质量为m的海螵蛸粉末，向分液漏斗中加入稀盐酸。在烧杯中加入足量氢氧化钠溶液，并称量烧杯及氢氧化钠溶液总质量m₁。

②先打开止水夹，再打开分液漏斗活塞，滴加盐酸并及时关闭活塞。完全反应后，

再次称量烧杯及其中液体的总质量m₂

③利用m₂与m₁的差值，即反应生成的二氧化碳质量，再计算海螵蛸中碳酸钙的含量。

   On the evening of October 7, Li Feng was watching TV while his mother was ____ b      cooking supper in the kitchen. ____ S       the telephone rang. Li Feng ____ q     picked it up to____ a        the call. It was from a good friend of his____ m     . She wanted to say “Happy Birthday” to his mother. "Today is Mother's birthday, but I have already____       f_____all about it. Mother gives me a lot of____ l      and care while I didn't care for her____ e    . From now on, I must always____ r     this, ____ s     my love to her and care for her enough,” Li Feng thought to himself, feeling a little ashamed(惭愧的).

根据下面的描述，在动物园示意图上标出各个馆的位置，并填空．

①动物园大门位于（5，0），向北走100m，到达熊猫馆．

②海洋馆位于 （  ，  ） ．

③大象馆位于（10，3）．

④狮虎山到熊猫馆和大象馆的距离相等．