Bīngxiāng lěngdòng shì jiéshuāng le yào chú yíxià.
The freezer has frosted up — we need to defrost it.
Tips
grammar
结 'to form / to tie' + 霜 'frost' — the verb 结 is productive for forming concrete depositions: 结冰 (freeze / ice up), 结露 (form dew), 结霜 (frost up), 结痂 (form a scab).
usage
Used both for natural frost (on plants, windows, the ground in late autumn) and appliance frost (freezer, AC). In weather forecasts you'll hear 地面结霜 ('the ground will frost over').
