题干

将新鲜马铃薯切成5cm的长条(粗细相同),分别放在浓度不同的甘露醇溶液中,4h后测量每条的长度,结果如图所示。以下有关分析不正确的是:                           (  )

A:马铃薯细胞液的浓度约为30g/L

B:在溶液浓度为20g/L,细胞发生质壁分离

C:在溶液浓度为40g/L~90g/L的范围内,细胞壁也有一定程度的收缩

D:当溶液浓度为40g/L时,细胞发生质壁分离

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答案(点此获取答案解析)

B

同类题4

任务型阅读

    “Urgent action required”, “Do you still want to hear from us?”, “We've updated our privacy policy”, “Should we stop sending you updates? If not, act now!”

    Many of us will have received emails like this during the past few weeks. Triggering this flood of emails is something called GDPR that comes into effect in just under two weeks' time. Often the emails warn that if you don't respond, you will be removed from the company's database, which raises a lot of questions. What action, if any, do you need to take? Could it affect you financially?

    GDPR, which stands for General Data Protection Regulation, has been described as the biggest overhaul(彻底检查)of online privacy since the birth of the internet. It is designed to give all EU citizens the right to know what data is stored on them and to have it deleted, plus protect them from privacy breaches(破坏). It comes into effect on 25 May.

    The new rules encourage the requirement for explicit and informed consent before data is processed. As a result, companies and organizations around the world are contacting users to check they are happy to carry on receiving their emails.

    However, many of us seem to be going down with “GDPR fatigue(厌倦)”: one article last week claimed that the “reconfirmation rate” - the proportion of people saying they want to continue receiving a company's emails - at UK micro-businesses was averaging just 10%, which meant “they could lose 90% of their subscribers - the life-blood for their business”. So it's no wonder some firms have adopted policies such as offering to enter people into a prize draw in return for them going in and updating their communication preferences.

    The average adult is said to have about 100 “data relationships” — companies and organizations that hold our personal data. Meanwhile, the reason why the company that occasionally emails you newsletters is now asking for your consent is perhaps because you never explicitly gave it permission to send you stuff. Maybe you only get its emails because you went to an event it organized ages ago or you once downloaded something from its website. Under the new regime, that almost certainly wouldn't count as explicit and informed consent, hence it's getting in touch now.

    The bottom line is that if it is a company or organization that you want to continue hearing from, you should probably click the button or log in to ensure you keep getting its emails. If it doesn't hear from you, it may decide to take you off its database.

Passage outline

Supporting details

The influences of

junk mails

◆ They flood into our lives.

◆ They____ to remove us from certain databases.

◆ They cause receivers to be____ about the possible risks.

The____of GDPR

◆ It will guarantee all EU citizens the____ to accept or refuse.

◆ It will require privacy ____from companies.

The ____from most receivers and the policies adopted by some firms

◆ Most receivers are____ to continue receiving such emails.

◆ Some firms hold activities so that people may win a ____ if they go in.

◆ Some firms offer to update people's communication preferences.

The reason and bottom line for companies sending such emails

◆ Companies hope to obtain explicit____ from their users.

◆ The information you left ____ doesn't mean you allow them to send you stuff.

◆ Without your reply, companies may take you off their databases.

同类题5

阅读下面文章,完成下列各题。

匀速奔跑

       ①我家附近有一所大学,每天晚上都有很多学生在那里跑步。

       ②一天下午,下班后我按照惯例驱车来到了学校体育场。这会儿,体育场上的人已有不少。我换上运动装,戴好耳机,听着富有激情的音乐,简单的做了几组热身运动之后便开始沿着跑道跑了起来。内心随之变得热血澎湃,感觉自己轻轻松松就能拿下一个马拉松。可是,当我跑到第二圈的时候我又开始喘了,脚步也随之慢了下来。很明显,因为我又胖了,我才变得比以前更容易透支。

       ③此时,一个身穿玫红色紧身背心和黑色运动裤的姑娘从我身边擦肩而过,速度不快但跑得明显很有节奏。我心想,自己怎么也不能让个姑娘把自己给超了,于是心一横,我紧赶了几步向前冲刺了50米,很轻松的把姑娘落在了后面。

       ④可我有限的体力还是支撑不起日渐增长的体重,慢慢的,我紧赶的步伐又缓了下来,一边双手掐腰喘着粗气,一边半走半跑挪着步子。正当我决定停下来慢走一圈时,红衣姑娘又一次从我身边跑了过去,还是那个速度和节奏。

       ⑤“超就超吧,哥们先走一走,缓一缓,等下体力恢复了再赶上你……”我心里不屑的盘算着。

       ⑥接下来我开始一边走一边观察着跑道上三三两两的人群,他们有的在一边慢走一边交谈,有的时而奔跑时而停下,有的跑得大汗淋漓,有的跑的漫不经心。

       ⑦跑步真的是一件很有意思的事情,它把你的体力、耐力和速度暴露无遗,并将你的性格从你跑步的姿势和神态上展露给别人。约摸走了两分钟,我觉得自己喘的不再那么痛苦,体力貌似又恢复了一些,决定继续跑。

       ⑧我不由得在体育场上寻找着那位刚刚超过我的红衣姑娘,心想这会我一定要赶上她。在前方扫了一眼后我没再看到她,我想她大概已经跑完回去休息了。结果,就在此时,一道红光从我的右侧闪了过去,没错,就是那个红衣姑娘,她又一次超过了我,还是那个匀速奔跑的节奏。我放弃了追赶红衣姑娘的念头。

       ⑨我开始寻找各种冠冕堂皇的理由,来解释自己追赶不上红衣姑娘的原因。但最终,我忽然明白了一个道理:如果不努力,那些匀速奔跑的人你永远追不上。

       ⑩匀速奔跑的人是可以掌控自己的人。他们会找到属于自己的节奏,在相对较长的一段时间里按照这个节奏去掌控自己。

       ⑪当一个人开始匀速奔跑起来的时候,他是在认真奔跑。当你还在踌躇要不要跑起来的时候,他们已经把你甩得遥不可及。

(文/河城子,摘自《知识窗》)