DAY 18 / 30 | 2026.10.1 · 周四 |
每天 5 分钟，和初二孩子一起精读一篇。今天是第 18 天。
一次有趣的实验 An Interesting Experiment 词数 220建议用时 6 分钟难度 ★★★☆☆ Yesterday our science teacher showed us an interesting experiment. A glass cup is filled with clean water by the teacher. A white egg is put into the cup, and it goes down to the bottom at once. We are very surprised because the egg cannot float. The cup is placed on the desk before the egg is dropped in. Then some salt is added to the water slowly. The water is stirred with a small spoon. After a while, the salt is dissolved and the water becomes salty. We watch the egg carefully and wait for a change. The reason is explained by the teacher in simple words. Little by little, the egg is lifted by the salty water. At last the egg is brought to the top and it floats on the surface. The result is seen by all of us, and we clap our hands happily. The teacher says the egg is held up because salty water is heavier. This experiment is loved by every student in the class. It is finished in ten minutes, but the lesson is remembered for a long time. Science is made interesting when we do it with our own hands. The steps are written on the blackboard so we can follow them. I think more fun lessons should be given to us. |
❑ 随堂测验QUIZ
1. What is put into the cup at the beginning of the experiment? A. The salt B. The white egg C. The spoon D. The blackboard |
2. Why does the egg float at last? A. Because the cup is placed on the desk. B. Because the teacher stirs the water. C. Because salty water is heavier and holds it up. D. Because the egg is dropped in quickly. |
3. The word "dissolved" in "the salt is dissolved" probably means ______. A. 溶解 B. 加热 C. 冷冻 D. 倒出 |
4. How do the students feel about this experiment? A. They are bored and leave early. B. They are surprised and happy, and they love it. C. They are angry with the teacher. D. They think it is too difficult. |
5. What is the best title for the passage? A. How to Cook an Egg B. An Interesting Experiment About Floating C. The Science Teacher D. How to Stir Water |
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先做题，再往下翻 ↓
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❑ 答案精讲ANSWERS
1B2C3A4B5B |
Q1 · B（细节题） 出处：第一段 "A white egg is put into the cup, and it goes down to the bottom at once" ▍ 抓被动句主语。第一段说 A white egg is put into the cup（一个白鸡蛋被放进杯子），开头放进去的是鸡蛋，B 一致；A 盐是后来加的、C 勺子是搅拌工具、D 黑板是写步骤的，都不是"被放进杯子"的东西，排除。 |
Q2 · C（细节/原因题） 出处：第三段末 "the egg is held up because salty water is heavier" ▍ 定位原因从句。老师明确解释 the egg is held up because salty water is heavier（鸡蛋被托起，因为盐水更重），C 一致；A 放杯子、B 搅拌、D 快速丢下都不是浮起来的真正原因，排除。 |
Q3 · A（词义猜测） 出处：第二段 "the salt is dissolved and the water becomes salty" ▍ 语境给线索。盐"被溶解"之后水变咸（becomes salty），说明 dissolved 是"溶解"；A 正确。B 加热、C 冷冻、D 倒出都和"水变咸"无关。 |
Q4 · B（推断题） 出处：第一段 We are very surprised、第三段 we clap our hands happily、第四段 is loved by every student ▍ 把情绪词串起来。学生先是 surprised（惊讶），看到结果 clap happily（开心鼓掌），结尾说 experiment is loved by every student（人人喜爱），所以又惊又喜且喜欢，B 最准；A 无聊早退、C 生气、D 嫌难文中都无依据。 |
Q5 · B（主旨题） 出处：全文讲一个让鸡蛋浮起来的科学小实验 ▍ 标题要罩住整篇。A 只讲煮蛋、C 只讲老师、D 只讲搅拌——都是局部；B 的 An Interesting Experiment About Floating（一个关于浮力的有趣实验）既点明"有趣实验"又点明"浮力"主题，最全面。 |
❑ 核心词汇卡VOCABULARY
experiment /ɪkˈsperɪmənt/ | n. 实验；试验 an interesting experiment 一个有趣的实验 |
float /fləʊt/ | v. 漂浮 the egg cannot float 鸡蛋浮不起来 |
dissolve /dɪˈzɒlv/ | v. 溶解 the salt is dissolved 盐被溶解 |
surface /ˈsɜːfɪs/ | n. 表面；水面 it floats on the surface 它浮在水面上 |
stir /stɜː(r)/ | v. 搅拌 The water is stirred with a small spoon 水被用小勺搅拌 |
heavier /ˈheviə(r)/ | adj. 更重的（heavy 的比较级） salty water is heavier 盐水更重 |
❑ 长难句拆解SENTENCE
The egg is held up because salty water is heavier. 翻译：鸡蛋被托了起来，因为盐水更重。｜ 今天核心语法——被动语态（Passive Voice）入门。当主语是"动作的承受者"而不是"发出者"时，用被动，结构 = be + 过去分词（done）。本文几乎句句被动：A glass cup is filled（杯子被装满）、The egg is put（鸡蛋被放）、The salt is added（盐被加）、The result is seen（结果被看见）。三步识别：① 找 be 动词（现在用 am/is/are，过去用 was/were）；② 看后面是不是过去分词（规则动词 +ed，如 filled/stirred/added，不规则如 held/dissolved/seen/given）；③ by 引出"谁做的"（常可省略，如 by the teacher）。最关键考点——被动不改变时态，时态由 be 动词决定：现在 is/are，过去 was/were。把今天 be + done 和 Day 12 的 be + doing（进行时）、Day 13 的 have + done（完成时）放一起，就是"助动词 / be 动词家族"一张卡。 |
主语(动作承受者) | The egg鸡蛋——它是"被托起"的，不是自己跳起来的 |
被动谓语 | is held upis + hold 的过去分词 held，构成被动：被托起 / 被举着 |
原因状语从句 | because salty water is heavierbecause 引导原因：因为盐水更重（这里更重是主动描述，不是被动） |
❑ 家长陪读贴士FOR PARENTS
01 | 找被动三步：和孩子一起圈出"be 动词（is/are/was/were）+ 过去分词"——主语是"被怎样"的承受者，by 后面才是动作的发出者（常省略）。比如 The water is stirred：水被搅拌，谁搅？by a spoon / by the teacher。 |
02 | 主动变被动：宾语变主语、谓语变 be + done、原主语变 by 短语。易错点是时态要一致：原句现在时配 is/are，过去时配 was/were；考试最爱考"be 动词时态写错"。 |
03 | 和前面时态做一张卡：被动只是"语态"换说法，时态仍由 be 决定。把今天 be + done（被动）、Day 12 be + doing（进行）、Day 13 have + done（完成）三兄弟并列，孩子一下就看清 be / have 这两个"助动词家族"成员。 |
❑ 明日预告TOMORROW
TOMORROW · DAY 19 《一个难忘的生日》A Memorable Birthday 话题：生日庆祝 ｜ 语法点：一般过去时被动语态（was/were + done，承接 Day 18 现在时被动做时态进阶） — 每天 19:30 更新 · 留言扣「打卡」— |
★本月 30 篇合集 PDF 私信「资料」即可领取 （含全文翻译 + 全部答案解析） |
