《国家中长期科学和技术发展规划纲要（2006 - 2020 年）》对我国科学和技术发展作出了全面规划与部署，并提出到2020 年使我国进入创新型国家行列。党的十八大报告进一步指出，必须把科技创新摆在国家发展全局的核心位置。

请问：

回答下列与实验相关的问题：

（1）“探充pH对酶活性影响”的实验中，向试管中添加（①淀粉②酸或碱③淀粉酶）这三种物质的正确顺序是　____ （填数字），理由是____

（2）据专家推测塑化剂有可能使儿童性早熟，为了探究塑化剂是否会导致儿童性早熟，某生物兴趣小组利用小白鼠做实验进行相关探究．（材料用具：略）

实验步骤：

①取生长发育状况等相同的成年雌性小白鼠3只分成三组，并编号为A、B、C；

②A组小白鼠用一定量饲料饲养，B组小白鼠用等量的拌有塑化剂溶液的饲料饲养，C组小白鼠用等量的拌有雌激素的饲料饲养；

③在相同适宜环境中饲养一段时间后，观察并记录各组小鼠的性成熟的快慢．

请分析回答：

a．该实验方案在步骤①有两处不妥，请纠正____ ；．

b．如果按更正后的实验进行，预测结果应是：若____ ，则说明塑化剂会使小鼠性早熟；若　____ ，则说明塑化剂不会使小鼠性早熟．

乐山一中某同学做了个小实验，他用一根细绳绑住家中洗脸池活塞，用活塞塞住洗脸池的漏口，然后往池中放满水。等到水面平静了，他用手拉住绳子，迅速上提，把活塞拨出。他看见水在下渗的过程中形成了漩涡。水面的漩涡应该是（   ）

阅读下面的短文，掌握大意，然后从每题所给A、B、C、D四个选项中选出最佳选项。

Dear Betty,

    Thank you very much for your email. I know you are new here and come to Wenzhou in your car. You want to know something old in Wenzhou. You say you'd like 1 Wenzhou Museum. It is a big and famous 2. It is near Shiji Square. Let me tell you the way to it. Take your car from your hotel and 3 along Fudong Road. Turn left at the third turning, not the 4 one. You will see Wenzhou Library 5your left. The museum is opposite the library. It 6from 9:00 to 5:00pm every day, except Monday. There are lots of 7 things and paintings in the museum. I think you can enjoy yourself there.8 don't take a camera, you can't use 9 in the museum. There is a small shop next to it. You can buy some souvenirs in it. And if you have enough 10, Wenzhou Science and Technology Museum is next to it. It is a good place to have fun, too.

    I think you'll have a good time in Wenzhou!

Yours,

Tom

2000÷500＝____

2700÷900＝____

2400÷200＝____