1)
Why does the Pasuk add the words "Kol Y'mei Hisgir oso"?
1.
Rashi: To preclude from the Din of Tum'ah the days that the owner is changing the stones and the mortar prior to the Hesger. 1
1
But not after the Kohen has declared it Tamei Muchlat, which is included in the Din of Tum'ah - since the Torah writes "Kol Yemei" (Rashi).
2)
Why doesw the Torah not mention Kibus Begadim in connection with someone who enters the Tamei house.
1.
Sifra: Because it is only someone who either eats in the house or lies down in it 1 who requires Kibus Begadim.
3)
Why does the Torah discuss one who enters the house, and not one who is already in the house?