Fell 是動詞 fall 的過去式。Fall 有「跌倒，摔倒；減少，降低；落下，降落」等意思，其動詞三態為 fall, fell, fallen。例如：
- Tim fell down the stairs and injured his head. (提姆跌下樓梯，頭部受了傷)
- Cindy slipped and fell on the ice, hurting her legs quite badly. (辛蒂滑了一跤，摔倒在冰上，雙腿受到重傷)
- Average temperatures fell by five degrees. (平均氣溫下降了五度)
- Share prices fell sharply this week. (本周股價急遽滑落)
- The snow fell all day in big white flakes. (雪下了一整天，大雪紛飛)
- Amy fell madly in love with her English teacher. (艾美瘋狂地愛上她的英文老師)
Felled 是動詞 fell 的過去式。Fell 意為「砍伐，砍倒 (樹木)；(尤指體育運動中) 擊倒」，其動詞三態為 fell, felled, felled。例如：
- The government felled a great number of trees to provide space for grazing. (政府砍伐大量樹木，為放牧提供場地)
- The heavyweight champion of the world eventually felled his opponent with a punch to the head. (這位世界重量級拳擊冠軍最後以頭部一記重拳擊倒對手)
Felt 是動詞 feel 的過去式。Feel 有「覺得；感到；認為；相信；觸，摸」等意思，其動詞三態為 feel, felt, felt。例如：
- Kevin felt like such an idiot. (凱文覺得自己是個十足的笨蛋)
- She felt his hot breath on her neck. (她感覺到她脖子上有他熱熱的氣息)
- Tom felt something crawling up his arm (湯姆覺得有東西順著他的手臂往上爬)
- Mary felt she would succeed this time (瑪麗相信她這次會成功)
- She felt the baby’s forehead and it was very, very hot. (她摸嬰兒的額頭，額頭非常非常燙)
Fall、Fell 和 Feel 這三個動詞不僅意思不同，動詞三態亦有很大的差異。儘管其過去式的拼字有些相近，但都不能互換。所以，在上面的例句中，任何一個過去式都不能用另兩個中的任一個來替代，否則就大錯特錯了！