下列各句中，没有语病的一句是（ ）

Unlike watching TV, reading is a highly active process _______ it requires attention as well as memory and imagination

I think he’s been drinking, _______ I’m not completelysure.

John, whose house is that? —It ______Mr White.

r to prevent the disease ___________ to other districts, the authorizedorganization killed thousands and thousands of cows