below 及under 的分別？

其實很難講它們的分別
它們在意義上差不多
但在用的時候就有別
例子一:"在桌子下面"
我們會說"under the table"
多過"below the table"
例子二: "十八歲以下"
我們可以說"below 18 or under 18"
總括來說, it depends!

below
–adverb
在下面;到下面;在下方;在樓下;在甲板下, 在下級;在某一級以下, 在水面(或地面)下, 在本頁下面(或下面一頁), 【書】在塵世上, 【口】(溫度)在零下, 在下游
1. in or toward a lower place: Look out below!
2. on, in, or toward a lower level, as a lower deck of a ship: The captain of the ship went below.
3. beneath the surface of the water: Divers were sent below to view the wreck.
4. on earth: the fate of creatures here below.
5. in hell or the infernal regions.
6. at a later point on a page or in a text: See the illustration below. Compare above (def. 5).
7. in a lower rank or grade: He was demoted to the class below.
8. under zero on the temperature scale: The temperature in Buffalo was ten below this morning.
9. Theater. downstage. Compare above (def. 8).
10. Zoology. on the lower or ventral side.

–preposition
(指位置)在...下面;到...下面, (指數量,程度等)在...以下, (指地位等)低於, 在...的下游, 有失...的身分;無...的價值
11. lower down than: below the knee.
12. lower in rank, degree, amount, rate, etc., than: below cost; below freezing.
13. too low or undignified to be worthy of; beneath: He considered such an action below his notice.
14. Theater. downstage of: There are two chairs below the table.

under
–preposition
在...下面,在...下方;在...裡面, 少於;低於;未滿, (表從屬)在...的管理(或統治,領導,監督)之下, 正在...之中;正受到;處於...情況之下, 根據,按照, 由於,因為, 屬於,歸入
1. beneath and covered by: under a table; under a tree.
2. below the surface of: under water; under the skin.
3. at a point or position lower or further down than: He was hit just under his eye.
4. in the position or state of bearing, supporting, sustaining, enduring, etc.: to sink under a heavy load.
5. beneath the heading or within the category of: Classify the books under “Fiction” and “General.”
6. as designated, indicated, or represented by: to register under a new name.
7. below in degree, amount, etc.; less than: purchased under cost.
8. below in rank; of less dignity, importance, or the like: A corporal is under a sergeant.
9. subject to the authority, direction, or supervision of: a bureau functioning under the prime minister.
10. subject to the instruction or advice of: to study the violin under Heifetz.
11. subject to the influence, condition, force, etc., of: under these circumstances; born under the sign of Taurus.
12. protected, controlled, or watched by: under guard.
13. authorized, warranted, or attested by: under one's hand or seal.
14. in accordance with: under the provisions of the law.
15. during the rule, administration, or government of: new laws passed under President Reagan.
16. in the state or process of: under repair; a matter under consideration.
17. Nautical. powered by the means indicated: under sail; under steam.

–adverb
在下面,在下方, 從屬地;服從地, 更低,更少,更小
19. beneath the surface.
20. in a lower place.
21. in a lower degree, amount, etc.: selling blouses for $25 and under.
22. in a subordinate position or condition.
23. in or into subjection or submission.

–adjective
下面的,下方的, 下級的,從屬的, 更低的,更少的,不足的
25. lower in position.
26. lower in degree, amount, etc.
27. lower in rank or condition.
28. subject to the control, effect, etc., as of a person, drug, or force: The hypnotist had her subject under at once. The patient was under as soon as he breathed the anesthetic.

—Verb
a. to give in; succumb; yield: She tried desperately to fight off her drowsiness, but felt herself going under.
b. to fail in business: After 20 years on the same corner they finally went under.