This cannot be answered. This will have to be written in English.
After you've knocked three times, if [the door] doesn't open, then I am not at home, or I can't come [to the door], or I choose to not be at home [for you] is the English equivalent of 'Ter tibi pulsanti si non aperitur non sum non possum non placet esse domi'. In the word by word translation, the adverb 'ter' means 'three times'. The personal pronoun 'tibi' means 'to thee, to you'. The verb 'pulsanti' means 'knocking'. The conjunction 'si' means 'if'. The adverb 'non' means 'not'. The verb 'aperitus' means 'it's opened'. The verb 'sum' means '[I] am'. The verb 'possum' means '[I] can'. The verb 'placet' means '[it] pleases'. The verb 'esse' means 'to be'. The noun 'domi' means 'at home'.
"If it is not opened at once when you knock three times" (Literally, "... to you knocking thrice")
The Latin word for please is "si placet."
The SI unit of mass is the kilogram.
The SI base unit for mass is the kilogram
The SI unit for mass is the kilogram.
The SI unit which is used to measure mass is the kilogram.
The SI unit for mass measurement is the kilogram (kg).
The SI unit of mass is the kilogram. However the prefixes are based on the gram.
The SI unit of mass is the kilogram (kg).
The SI unit for mass is kilogram, or kg for short.
Kilogram is the SI unit for mass.