夜以继日 yè yǐ jì rì

DEFINITIONS

  1. night and day (idiom); continuous strenuous effort

CHARACTERS

夜 yè
HSK 5
night, dark; in night; by night
以 yǐ
HSK 2
by means of; thereby, therefore; consider as; in order to
继 jì
HSK 4
continue, maintain, carry on
日 rì
HSK 2
sun; day; daytime