一旦養成了壞習慣,就很難改回來了。

A bad habit, once formed, is difficult to get rid of.

Source: Tatoeba

Sentence Composition

1 一旦 dàn
  1. in case (sth happens)
  2. if
  3. once (sth happens, then...)
  4. when
  5. in a short time
  6. in one day
2 養成 yǎngchéng
  1. to cultivate
  2. to raise
  3. to form (a habit)
  4. to acquire
=3 le
  1. (completed action marker)
  2. (modal particle indicating change of state, situation now)
  3. (modal particle intensifying preceding clause)
=3 liǎo
  1. to finish
  2. (used with or after a verb to express (im)possibility, as in 忘不了 wàngbuliǎo "cannot forget")
  3. (literary) (usually followed by a negative such as or ) completely (not); entirely (not); (not) in the least
  4. to understand clearly (variant of liǎo)
=3 liǎo
  1. (of eyes) bright
  2. clear-sighted
  3. to understand clearly
=3 liào unofficial variant of liào
4 huài
  1. bad
  2. spoiled
  3. broken
  4. to break down
  5. (suffix) to the utmost
5 習慣 guàn
  1. habit
  2. custom
  3. usual practice
  4. to be used to

classifier:

6 jiù
  1. (after a suppositional clause) in that case; then
  2. (after a clause of action) as soon as; immediately after
  3. (same as 就是 jiùshì) merely; nothing else but; simply; just; precisely; exactly
  4. only; as little as
  5. as much as; as many as
  6. to approach; to move towards
  7. to undertake; to engage in
  8. (often followed by zhe) taking advantage of
  9. (of food) to go with
  10. with regard to; concerning
  11. (pattern: jiù ... ...) even if ... still ...
  12. (pattern: ... jiù ...) if not ... then must be ...
7 hěn
  1. very; quite
  2. (also, often used before an adjective without intensifying its meaning, i.e. as a meaningless syntactic element)
=8 nán
  1. difficult (to...)
  2. problem
  3. difficulty
  4. difficult
  5. not good
=8 nàn
  1. disaster
  2. distress
  3. to scold
9 gǎi
  1. to change
  2. to alter
  3. to transform
  4. to correct
=10 回來 huílai to return; to come back
=10 回來 huílái
  1. (to come or bring) back (used after a verb to indicate direction towards the speaker)
  2. back (used after a verb to indicate direction towards the speaker)
  3. to return; to come back; to be back
=11 le
  1. (completed action marker)
  2. (modal particle indicating change of state, situation now)
  3. (modal particle intensifying preceding clause)
=11 liǎo
  1. to finish
  2. (used with or after a verb to express (im)possibility, as in 忘不了 wàngbuliǎo "cannot forget")
  3. (literary) (usually followed by a negative such as or ) completely (not); entirely (not); (not) in the least
  4. to understand clearly (variant of liǎo)
=11 liǎo
  1. (of eyes) bright
  2. clear-sighted
  3. to understand clearly
=11 liào unofficial variant of liào