"of the plague-spot": This refers to (tearing out) the white hair.
"of leprosy": This refers to the michyah (viz. Vayikra 13:24). This tells me (that he is liable) only for (cutting) all of them. Whence do I derive (the same for) some of them? From "to heed it exceedingly and to do."
This tells me only of plague-spots of men. Whence do I derive (the same for) plague-spots of garments and plague-spots of houses? From "according to all that the Cohanim, the Levites, teach you."
This tells me (of liability) only in the instance of confirmation (of the plague-spot). Whence do I derive (the same for the instance of) quarantine and non-designation of "uncleanliness" (tumah)? From "as I have commanded them."