问题 问答题

星期天,小明和妈妈一起去买电热水器,在眼花缭乱的商品中,售货员极力推荐的一种电热水器引起了小明的注意.这种电热水器叫即热式电热水器,又叫快热式电热水器.售货员熟练地说出了以下5条优点:①不需预热;②节能省电;③不易结水垢;④体积小巧;⑤水温恒定.

果真如此吗?小明和妈妈把这种新型的热水器和传统热水器进行了对比,发现传统的热水器有一个较大的水箱,当水箱内的水达到合适的温度才可以使用,而这种电热水器没有水箱.第④条优点是显然的.其他4条优点可信吗?

答案

答:①因为没有水箱,所以可边加热边使用.所以“不需预热”可信.

②因为即热式电热水器和箱式电热水器相比,减少了加热直至温度合适前以及温度合适后等待过程中散热造成的能量损失.所以“节能省电”可信.

③其加热原理是靠电热丝加热体本身的高温把冷水加热的,即使在停止工作后,因加热体本身留有余温,并且余温温度极高,所以发热杯内的水会借加热体的余温达到70度以上,再加上即热式本身的加热杯内无镁棒,杯内少量水是静止的,结垢是必然的.所以“不易结水垢”不可信.

⑤因为单位时间内通过的水流量相同,发热功率相同,所以“水温恒定”可信.

选择题
完形填空
阅读下面短文,掌握其大意,从每题所给的A、B、C、D四个选项中,选出最佳选项,并在答题卡上将该项涂黑。
It’s Saturday morning. Tony’s sitting at the kitchen table,    36    with a piece of bread. He’s not even    37   . Is he ill? No, but he does have a    38   . He has nothing to do because the Internet is down. When he    39    up this morning, Tony was feeling    40   . He jumped out of bed full of plans for the weekend    41   . It would be a weekend like any other --- a great weekend. But that was    42    he turned on his computer and    43    he was unable to go online. Having no Internet changes everything.
Every weekend, Tony    44    goes online to email friends, read the    45    to keep up with what’s happening in the world and    46    a few online chess games with his cousin Helen to finish the weekend off. The perfect weekend --- online!
Just as Tony is    47    how he can possibly have a normal weekend without the Internet, his mum walks into the    48   . “Cheer up, Tony. Don’t    49    the Internet any more, OK?” Tony makes no    50    but sighs (叹气).“Go and play chess with Helen!” Tony’s mum­  51   .
“Oh, yes! Helen lives just around the    52   . We can meet and play chess face to face for a    53   . Maybe this weekend won’t be so bad,” Tony    54   , as he walks to the phone. There is   55    without the Internet after all.
小题1:
A.cutting B.playingC.eatingD.thinking
小题2:
A.hungryB.angryC.tiredD.sleepy
小题3:
A.fearB.problemC.businessD.thing
小题4:
A.roseB.rangC.lookedD.woke
小题5:
A.greatB.disappointedC.unhappyD.worried
小题6:
A.alsoB.aboveC.aheadD.ago
小题7:
A.afterB.beforeC.until D.when
小题8:
A.thoughtB.guessedC.decidedD.found
小题9:
A.usuallyB.nearlyC.especiallyD.already
小题10:
A.lettersB.newsC.reportsD.contents
小题11:
A.guess B.takeC.playD.make
小题12:
A.provingB.wonderingC.realizingD.remembering
小题13:
A.living-roomB.hallC.kitchenD.study
小题14:
A.talk aboutB.care aboutC.think aboutD.look about
小题15:
A.answerB.progressC.movementD.choice
小题16:A requests              B. replies                    C. tells                                  D. suggests
小题17:
A.edgeB.distanceC.cornerD.end
小题18:
A.chatB.timeC.lessonD.change
小题19:
A.continuesB.smilesC.readsD.watches
小题20:
A.changeB.taskC.weekendD.life