以下是小学三年级需要掌握的英语单词：

1. apple
2. banana
3. orange
4. pear
5. watermelon
6. strawberry
7. grape
8. pineapple
9. lemon
10. peach
11. cat
12. dog
13. bird
14. fish
15. rabbit
16. mouse
17. turtle
18. frog
19. panda
20. monkey
21. giraffe
22. elephant
23. lion
24. tiger
25. bear
26. horse
27. cow
28. sheep
29. pig
30. chicken
31. duck
32. goose
33. turkey
34. school
35. teacher
36. student
37. desk
38. chair
39. book
40. pencil
41. pen
42. eraser
43. ruler
44. backpack
45. classroom
46. playground
47. game
48. toy
49. bicycle
50. car
51. bus
52. train
53. plane
54. ship
55. beach
56. park
57. zoo
58. museum
59. library
60. hospital
61. doctor
62. nurse
63. dentist
64. police
65. fireman
66. postman
67. family
68. mother
69. father
70. brother
71. sister
72. grandmother
73. grandfather
74. aunt
75. uncle
76. cousin
77. friend
78. happy
79. sad
80. angry
81. tired
82. hungry
83. thirsty
84. hot
85. cold
86. big
87. small
88. tall
89. short
90. long
91. fast
92. slow
93. old
94. young
95. beautiful
96. ugly
97. clean
98. dirty
99. good
100. bad