小明注意家里摆钟的钟摆在有规律地摆动，经认真观察发现钟摆来回摆动一次的时间刚好是1秒，就想：是不是所有的摆来回摆动一次的时间都是1秒呢？于是，他请教了物理老师，知道摆来回摆动一次的时间叫做周期，在老师的指导下他设计如图2所示的单摆（即细绳下系一小钢球）进行探究 。

验数据记录如下表：

能源、环境、材料与人类的生活息息相关．根据所学知识回答下列问题．
（1）水是生命之源，保护水资源从我做起．
①电解水试验中，往水中加入少量氢氧化钠的目的是____，试验时若正极产生6ml气体，则负极产生气体的体积是____mL，该实验证明了水是由____组成的．
②生活中常用____来降低水的硬度．如图所示是常用自制净水器，其中活性炭的作用是____；制造塑料瓶的材料属于____材料．请介绍一种你的节水方法____．

（2）化石燃料是有限的，大量使用会导致环境污染．请你例举一种清洁能源____．

增加：在缺词处加一个漏字符号（∧），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。

    Everyone should take the action to reduce haze (雾霾), which is harmless to our health. First of all, I believe that if we plant more tree, there will be less haze in their city. Trees can absorb exhaust fumes (尾气) from cars, thus reduce pollution. Second, the government should punish the factories where produce too many fumes. Exhaust fumes is the main cause of haze and do greatly harm to people's health. Maybe we can move factories to areas where few people live. Third, I think it was a great idea to encourage people to use public transportation. Last but not least, we can call on citizens ride bikes if they travel short journeys.

 根据题意，回答下列问题：

    It seems that many stars are putting their fashion (时尚) skills to good use and some of them have succeeded in designing.

    Avril Lavigne

    “With a lot of designs, I try to tie in with some of my lyrics and more musical elements,” Lavigne said. Her product, named after a childhood nickname (绰号) from her father, was created three years ago, but Lavigne came up with the first idea for a clothing product when she was only 19 years old.

Victoria Beckham

    Victoria created her own style of jeans for the clothing brand (品牌) Rock & Republic in 2004. Later, she created her own brand with the name DVB style and now she is more popular as a designer than as a singer.

    Madonna

    Pop queen Madonna created her fashion products in collaboration (合作) with the Swedish clothing company Hennes & Mauritz AB ( H&M) in 2007. She then collaborated with her daughter Lourders in creating 2010 juniors' product for Macy's called “Material Girl”.

    Jessica Simpson

    Jessica Simpson created her own collection of jeans. She worked with the Camuto Group and Jones Apparel Group Inc.

    Justin Timberlake

    No one could imagine that Justin would become a fashion designer until he paired with his friend Trace Ayala to create the William Rast label. Their clothing is presented every season and attracts attention of Timberlake's fans and models.