单词填空。根据句子内容和所给首字母填入适当的单词。

1. Mike usually goes to school by bus, but today he goes by b______.

2. The 2008 Olympic G______ will be held in Beijing.

3. Bill says he wants to j______the army when he grows up.

4. A stranger was knocking at the door, but she was afraid of  l______ him in.

5. Her mother became s______ ill and had to be sent to hospital at once.

某同学设计了一套实验方案研究第11-18号部分元素的性质变化

（1）指出②中的实验现象：_______________________

（2）实验Ⅰ的设计中能达到实验目的的实验项目是___________（填序号）

（3）写出③中发生反应的离子方程式：______________________ 

（4）④中密封油H₂S的玻璃管加热后出现黄色固体，分析产生这种现象的原因是：_________________。密封有HCl的玻璃管无明显现象。该实验说明非金属性：S_______Cl（填“强于”或“弱于”）