他們突然一起大笑了起來。

All at once they began to laugh.

Source: Tatoeba

Sentence Composition

1 他們 tāmen they; them
2 突然 tūrán sudden; abrupt; unexpected
3 一起 yīqǐ
  1. (in) the same place
  2. together; in company (with)
  3. altogether; in total
  4. an instance of; a case of (murder, accident, dispute etc)
4 大笑 dàxiào
  1. to laugh heartily
  2. a belly laugh
=5 了 le
  1. (completed action marker)
  2. (modal particle indicating change of state, situation now)
  3. (modal particle intensifying preceding clause)
=5 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)
=5 了 liǎo
  1. (of eyes) bright
  2. clear-sighted
  3. to understand clearly
=5 了 liào unofficial variant of 瞭 liào
=6 起來 qǐlai
  1. to stand up; to get up
  2. also pr. qǐlái
=6 起來 qilai
  1. (after a verb) indicating the beginning and continuation of an action or a state
  2. indicating an upward movement (e.g. after 站 zhàn)
  3. indicating completion
  4. (after a perception verb, e.g. 看 kàn) expressing preliminary judgment
  5. also pr. qǐlai
=6 起來 qǐlái
  1. placed after a verb to form a copular verb, expressing evaluation based on initial perception
  2. placed after a verb to indicate that the action has started
  3. to get up; to get out of bed
  4. to rise up; to get up