揸火箭 [－－－]

Jyutping zaa1 fo2 zin3
Pinyin zhā huǒ jiàn

Definitions (粵典–words.hk)
  1. 動詞、香港
    喺​學​科​或​公​開​考​試​入​面​攞​到​A
    to get an 'A' grade in a school subject