三年级：
1. 家庭与日常用品：family, home, mother, father, brother, sister, grandparent, grandpa, grandma, aunt, uncle, cousin, bed, table, chair, sofa, lamp, window, door, TV, phone, book, pencil, ruler, backpack, schoolbag, desk, computer, mouse, keyboard。
2. 食物与饮料：apple, banana, orange, pear, watermelon, grape, cake, bread, rice, noodles, meat, chicken, fish, milk, water, juice, tea, coffee。
3. 动物与植物：cat, dog, bird, rabbit, pig, cow, sheep, horse, tree, flower, grass, leaf, root, branch。
4. 颜色与形状：red, blue, green, yellow, black, white, purple, orange, round, square, triangle, rectangle。
5. 数与量：one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, twenty, one hundred, many, some, few, a lot of, little, much。
四年级：
1. 学校与课程：teacher, student, classroom, school, lesson, subject, math, Chinese, English, science, music, PE, art, homework, notebook, textbook, uniform, school uniform, uniform shirt, tie, skirt, pants, shoes。
2. 季节与天气：spring, summer, autumn, winter, season, weather, sun, moon, star, cloud, rain, snow, wind, temperature, hot, cold, warm, cool。
3. 节日与庆祝：Christmas, New Year, birthday, festival, party, present, gift, card, decoration, tree, light, firecracker, dragon, lion。
4. 与语言：country, USA, China, English, Chinese, French, Spanish, language, speak, talk, say。
5. 职业与人物：doctor, nurse, teacher, farmer, driver, man, worker, engineer, scientist, artist, singer, actor, model。
五年级：
1. 交通工具与旅行：bus, car, train, plane, ship, bike, motorcycle, helmet, ticket, station, airport, travel, trip, hotel, room, restaurant, menu, order, food court。
2. 运动与健身：sport, game, soccer, basketball, volleyball, tennis, swim, run, jump, high jump, long jump, fitness, healthy, exercise。
3. 情感与态度：happy, sad, angry, scared, excited, bored, tired, helpful, friendly, polite, impolite, rude, nice, kind。
4. 节日与习俗：Halloween, Thanksgiving, Easter, Valentine’s Day, Mid-Autumn Festival, Spring Festival, custom, tradition, celebrate, festival。
六年级：
1. 地理与自然：continent, country, city, town, village, nature, forest, river, lake, mountain, desert, plain, volcano, earthquake, weather, climate。
2. 科技与发明：robot, computer, internet, email, phone, TV, camera, game console, invent, discover, technology。
3. 与健康：body, head, face, hair, eye, nose, mouth, ear, neck, arm, hand, finger, leg, foot, toe, health, illness, disease, healthy, unhealthy。
4. 环保与保护：environment, pollution, air pollution, water pollution, noise pollution, recycle, reuse, reduce, protect, conservation, nature reserve。
以上是小学3到6年级英语单词的重点词汇整理，每个年级的词汇都涵盖了不同的主题和类别，帮助学生更好地掌握和应用这些词汇。