传播学者克罗斯曾提出一个“谣言公式”：谣言=事件的重要性×事件的模糊性×公众批判能力，这说明谣言的能量有多大，既取决于真实信息的透明度，也取决于受众的判断水平。打击网络谣言，正确发挥互联网的作用，应该（  ）

①提升网络参与者的素养

②增强公民的民主管理能力

③提高政府的行政管理水平

④限制网络信息的传播和扩散

甲、乙两车在同一地点同时沿同一方向做直线运动，其v﹣t图象如图所示，则（   ）

    Linda: Hello, George.____ 

    George: Hi, Linda. I'm reading a tourist guide to Europe.

    Linda:____ 

    George: Yes, i'm looking to such a trip. Hey, have you ever been there?

    Linda: Yes. I've actually visited my countries in Europe; France, Germany, Italy and Austria, for example.

    George:____ And how long did you stay?

    Linda: Two years ago. For over one month.

    George: Did you like it?

    Linda:____There are many ancient churches and castles. It's the best trip I've ever taken.

    George: Sounds great.____ 

    Linda: Good idea. You won't regret it.

A: Of course.

B: Not exactly.

C: What are you doing?

D: When did you go there?

E: Do you plan to move to Europe?

F: Are you thinking of visiting Europe some day?

G: I decide to make a trip next October on my annual leave.

某兴趣小组的同学为了探究酒精对水蚤心率的影响，在15℃的室温条件下，选用40只大小一致、生命活力相同的成年水蚤分成四组，分别放置在体积分数为5%、10%、15%、20%的酒精溶液中，依次观察了水蚤10秒心跳次数，结果如下：

（提示：因水蚤心跳太快，为减少误差，实验中只计算10秒的水蚤心跳次数．）