根据中文提示完成句子填空。

根据短文内容，选择所给词的适当形式完成短文。                

The most important person in the world is your mother. She looks after you all the ____ .On cold winter days, she always tells you ____on more clothes. She always stands in the wind waiting for you back from school every day. When you hurry to leave home for school without breakfast, she always feels ____  about you at home. She knows about your study and spends much money ____ your school things. Mother can do everything for you day after day. What ____  love that is in the world! We’ll always remember mother love.

根据观察现象回答下列问题．

实验步骤如下：

①将一些糖和酵母菌放入烧瓶，并加入一些温开水，摇晃均匀．

②将一个未充气的小气球套在烧瓶口上．

③将烧瓶放在比较温暖的地方，每天观察．

（1）烧瓶中会有什么现象发生？____ ．

（2）套在烧瓶上的小气球会出现什么现象？____ ，为什么？____  ．

（3）将烧瓶中的水与酵母菌、糖充分摇匀的目的是____ 

（4）为什么要将烧瓶放在温暖的地方？如果放在温度较低的地方，会有什么结果？____  

（5）如果烧瓶中只放酵母菌和水，上述现象能否发生？为什么？____  ．