Subject + 掉 + 了 / Verb + 掉
掉 (diào) is a verb meaning "to fall," "to drop," or "to lose." It is also widely used as a resultative complement after other verbs to indicate that something has been removed, lost, or completed, as in 丢掉 (to throw away) or 忘掉 (to forget).
手机掉到水里了,怎么办?
Shǒujī diào dào shuǐ lǐ le, zěnme bàn?
My phone fell into the water — what should I do?
她把不需要的旧衣服都扔掉了。
Tā bǎ bù xūyào de jiù yīfu dōu rēng diào le.
She threw away all the old clothes she didn't need.
树上的叶子一片一片地掉下来了。
Shù shàng de yèzi yí piàn yí piàn de diào xiàlái le.
The leaves fell from the tree one by one.