四月底，黄河的水发黑了。

At the end of April, the water of the Yellow River had darkened.

Source: Tatoeba

Sentence Composition

=1 四月 Sìyuè
  1. April
  2. fourth month (of the lunar year)
=1 四月 sìyuè
  1. April
  2. The modern name for the fourth month of the Chinese lunar calendar.
=2 底 de (equivalent to 的 as possessive particle)
=2 底 dǐ
  1. bottom; base
  2. background; foundation
  3. copy (of a manuscript or receipt etc) kept as a record
  4. (suffix) end of a year or month
  5. (math.) radix; base (abbr. for 底数 dǐshù)
3 黄河 Huáng Hé Yellow River or Huang He
=4 的 de
  1. of; ~'s (possessive particle)
  2. (used after an attribute when it modifies a noun)
  3. (used at the end of a declarative sentence for emphasis)
  4. (used after a noun, verb or adjective to form a nominal expression, as in 皮革的 pígéde "one made of leather" or 跑堂儿的 pǎotángrde "a waiter (literally, one who runs back and forth in a restaurant)" or 新的 xīnde "new one")
  5. also pr. dì or di in poetry and songs
=4 的 dī a taxi; a cab (abbr. for 的士 dīshì)
=4 的 dí really and truly
=4 的 dì (bound form) bull's-eye; target
5 水发 shuǐfā to steep in water
=6 黑 Hēi abbr. for Heilongjiang province 黑龙江 Hēilóngjiāng
=6 黑 hēi
  1. black
  2. dark
  3. sinister
  4. secret
  5. shady
  6. illegal
  7. to hide (sth) away
  8. to vilify
  9. (loanword) to hack (computing)
=7 了 le
  1. (completed action marker)
  2. (modal particle indicating change of state, situation now)
  3. (modal particle intensifying preceding clause)
=7 了 liǎo
  1. to finish
  2. (used with 得 dé or 不 bù after a verb to express (im)possibility, as in 忘不了 wàngbuliǎo "cannot forget")
  3. (literary) (usually followed by a negative such as 无 wú or 不 bù) completely (not); entirely (not); (not) in the least
  4. to understand clearly (variant of 了 liǎo)
=7 了 liǎo
  1. (of eyes) bright
  2. clear-sighted
  3. to understand clearly
=7 了 liào unofficial variant of 瞭 liào