问题 读图填空题

准备紫皮洋葱、30%蔗糖溶液、清水、载玻片、盖玻片、吸水纸、吸管、镊子和显微镜,做如下实验:

①制作洋葱表皮细胞临时装片,在显微镜下找到洋葱表皮细胞的清晰图像。如图中A所示。

②在临时装片的盖玻片的一侧滴加少许30%蔗糖溶液,用吸水纸从另一侧吸引,重复几次,使细胞浸在蔗糖溶液中,在显微镜下观察到细胞渐渐变成图中B所示的形态。

③在盖玻片的一侧滴加清水,用吸水纸从另一侧吸引,重复几次,使细胞浸入清水中,在显微镜下观察到细胞变化为图中c所示的形态。

【分析回答下列问题】:

(1)在第②步实验操作之后,细胞中的液泡明显变_____,这是因为细胞周围的蔗糖溶液浓度________细胞液浓度,细胞_________的缘故。

(2)在第③部操作之后,细胞中的液泡明显变______,这是因为细胞周围的溶液浓度_______细胞液浓度,细胞__________的缘故。

(3)以上实验说明:细胞吸水或失水,取决于                                           的浓度。当              浓度大于                        浓度时,细胞吸水;当                 浓度大于                           浓度时,细胞失水。

答案

(1)小 大于 失水

(2)大 小于 吸水

(3)细胞液的浓度 细胞周围的溶液 细胞液 细胞周围的溶液 细胞液

完形填空

When are you an adult (成年人)?
When do you think you are an adult ? Maybe different __31_ have different ideas.
Now let’s see what some American teenagers(青少年)say .
Sam: In  32 idea ,you are an adult at the  33  of 18. That’s when you can vote(投票)。You can help to   34  who rules(统治)the whole country .That’s also a grown-up does! My grandfather couldn’ t vote   35 he was 21.They changed(改变) it to 18 in 1971.
Jenny:I don’t 36  it’s hard to say . I can drive a car at 16, can’t I ?When you have a driver’s licence , you can 37 it to people to tell them your age for all kinds of things .  38    sixteen must be the age when you change from a  39  person to an adult.Because you can tell others you are not a  40   any more .
Suzie : Well , I think there is  41   wrong with American laws for when young people can  42  things . I can vote at 18 and drive at 16. So you would think 18 is a grown-up,  43  16 isn’t .But then I can’t drink wine(酒)until I’m 21 ! If I’m 44   an adult at 18, how can people stop me from  45   a cup of beer in a bar ?
小题1:
A.teenagersB.adultsC.driversD.grandfather
小题2:
A.hisB.myC.herD.your
小题3:.
A.ageB.endC.frontD.number
小题4:
A.makeB.keepC.choose(选择)D.teach
小题5:
A.afterB.untilC.whenD.if
小题6:
A.hopeB.wantC.likeD.think
小题7:
A.showB.sendC.askD.pass
小题8:
A.ButB.AndC.SoD.Or
小题9:
A.oldB.youngC.littleD.tall
小题10:
A.babyB.group-upC.boyD.kid
小题11:
A.anythingB.everythingC.somethingD.nothing
小题12:
A.doB.buyC.likeD.borrow
小题13:A,as if           B.even though    C.ever since    D.above all
小题14:
A.alreadyB.stillC.alsoD.yet
小题15:
A.sellingB.makingC.drinkingD.giving
填空题