P3 科学 真题样题

正确答案：C. R

考点材料的吸水性：做雨衣的材料 · Absorbency: choosing material for a raincoat

思路：剩下的水越多，说明材料吸的水越少。R 一点水都没吸（还剩 20 ml），最防水，最适合做雨衣。
Think: The more water left in the beaker, the less water the material soaked up. R absorbed no water (20 ml left), so it is the best for a raincoat.
小提醒：做雨衣要选不吸水的材料。
Tip: A raincoat needs a material that does not absorb water.

正确答案：C. G

考点磁铁：比较磁力强弱 · Magnets: comparing magnetic strength

思路：d 是磁铁要移动多远才能吸到钉子。磁力越强，离钉子还很远就能吸住，所以要移动的距离越短。G 只要移动 2 cm，最短，磁力最强。
Think: d is how far the magnet had to move before it attracted the pin. A stronger magnet attracts the pin from further away, so it needs to move less. G moved only 2 cm, so G is the strongest.
小提醒：这里 d 越小，磁力越强。
Tip: Here, the smaller d is, the stronger the magnet.

正确答案：B.

考点蚊子的生命周期：卵、幼虫、蛹、成虫 · Life cycle of a mosquito: egg, larva, pupa, adult

思路：A 是成虫，B 是蛹，C 是幼虫，D 是浮在水面的卵。正确顺序：卵 D → 幼虫 C → 蛹 B → 成虫 A → 卵 D。选项 2 顺着箭头是 C → B → A → D → C，正好符合。
Think: A is the adult, B the pupa, C the larva and D the eggs. The order is D → C → B → A → D. Option 2 reads C → B → A → D → C, which matches.
小提醒：顺着箭头一个一个读，看看是不是“卵→幼虫→蛹→成虫”。
Tip: Follow the arrows and check: egg → larva → pupa → adult.

正确答案：A. A and B

考点磁铁：电磁铁的公平测试 · Magnets: fair test for an electromagnet

思路：只能改变线圈的圈数，电池数量要一样。A 和 B 都用 3 个电池，圈数分别是 10 和 20，所以选 A 和 B。
Think: Only the number of turns should change; the number of batteries must stay the same. A and B both use 3 batteries with 10 and 20 turns. So A and B.
小提醒：电池越多，电磁铁也越强，所以电池数量一定要一样。
Tip: More batteries also make the electromagnet stronger, so keep the batteries the same.

正确答案：D. H

考点分类图：开花植物 · Flow chart: classifying a flowering plant

思路：X 是会开花的植物。它需要空气、食物和水（是）→能自己制造食物（是）→会结果实（开花植物会结果，是）→ 到达 H。
Think: X is a flowering plant. Needs air, food and water? Yes. Can make its own food? Yes. Produces fruits? Yes, flowering plants produce fruits. So X ends at H.
小提醒：按流程图一格一格回答“是 / 否”。
Tip: Answer each box Yes or No, one step at a time.

正确答案：C. X and Z only

考点材料的强度：读图比较承重 · Materials: comparing strength from a diagram

思路：要承受 6 kg 不断，绳子最大承重要至少 6 kg。W 5 kg、Y 3 kg 不够；X 7 kg、Z 10 kg 够。所以是 X 和 Z。
Think: To hold 6 kg, a string must support at least 6 kg. W (5 kg) and Y (3 kg) are not enough. X (7 kg) and Z (10 kg) are. So X and Z only.
小提醒：把每个数和 6 比一比。
Tip: Compare each number with 6.

正确答案：B. 12

考点生命周期：读条形图计算天数 · Life cycles: reading a bar graph to find days

思路：从卵到成虫要经过卵、幼虫、蛹三个阶段：2 + 4 + 6 = 12 天。成虫阶段的 14 天不用算进去。
Think: To become an adult, the insect goes through egg, larva and pupa: 2 + 4 + 6 = 12 days. The 14 days as an adult are not counted.
小提醒：注意“到变成成虫为止”，不包括成虫期。
Tip: “Become an adult” means stop counting when the adult stage begins.

正确答案：A. W

考点动物分类：用表格辨认动物（海豚） · Animal groups: using a table to identify a dolphin

思路：海豚会游泳，不产卵（它是哺乳动物，直接生小海豚）。W 只有“会游泳”这一项，最符合海豚。Y 会产卵，所以不是海豚。
Think: A dolphin can swim and does not lay eggs (it is a mammal and gives birth to its young). W only has "can swim", so W fits best. Y lays eggs, so it is not a dolphin.
小提醒：海豚住在水里，但它是哺乳动物，不是鱼。
Tip: A dolphin lives in water but is a mammal, not a fish.

正确答案：D. Set-up D

考点霉菌生长需要水分和温暖 · Mould needs moisture and warmth to grow

思路：霉菌生长需要水分、空气、食物和适合的温度。D 的饼干洒了水，水分最多，而且在室温下，所以霉菌最先长出来。B 去掉了水分，C 放在冰箱里太冷，都长得慢。
Think: Mould needs water, air, food and warmth. Set-up D has the most water and is at room temperature, so mould grows there first.
小提醒：湿 + 温暖 = 霉菌长得快。
Tip: Damp and warm = mould grows fast.

正确答案：D. respond to changes around them

考点生物的特征：对周围变化有反应 · Characteristics of living things: respond to changes

思路：Lena 碰了含羞草，叶子马上合起来。这是植物对“被碰”这个变化作出的反应。
Think: Lena touched the mimosa and its leaves folded up at once. The plant responded to a change (the touch).
小提醒：被碰、遇光、遇热马上有变化，就是“对变化有反应”。
Tip: A quick change after a touch, light or heat means the living thing responds to changes.