under 和 below 的中文意思都是 "在...下面/之下"。如果只是指 B 物的位置在低於 A 物的地方, 那麼兩者可以通用。比如: My office is two floors under / below the first floor. 通常會用 under 的情況：(1) 某個東西被另一個東西遮蓋隱藏住了，像是：I hid the money under a tree. / He wore a T-shirt under the shirt. (2) 指未達某個年紀或數字少於...，像是：The show is free for children under 12. / His weight has dropped under 90 lbs. (3) 某些固定用法的片語，例如：under attack, under arrest, under pressure, under control, under the circumstances…... 或其他這方面意思的字詞。較常用 below 的情況：(1) 不是正
