I could waterproof you could waterproof he could waterproof we could waterproof you could waterproof they could waterproof
V-ing form
I could be waterproofing you could be waterproofing he could be waterproofing we could be waterproofing you could be waterproofing they could be waterproofing
Perfect
I could have waterproofed you could have waterproofed he could have waterproofed we could have waterproofed you could have waterproofed they could have waterproofed
V-ing perfect
I could have been waterproofing you could have been waterproofing he could have been waterproofing we could have been waterproofing you could have been waterproofing they could have been waterproofing
Negation
Simple form
I couldn't waterproof you couldn't waterproof he couldn't waterproof we couldn't waterproof you couldn't waterproof they couldn't waterproof
V-ing form
I couldn't be waterproofing you couldn't be waterproofing he couldn't be waterproofing we couldn't be waterproofing you couldn't be waterproofing they couldn't be waterproofing
Perfect
I couldn't have waterproofed you couldn't have waterproofed he couldn't have waterproofed we couldn't have waterproofed you couldn't have waterproofed they couldn't have waterproofed
V-ing perfect
I couldn't have been waterproofing you couldn't have been waterproofing he couldn't have been waterproofing we couldn't have been waterproofing you couldn't have been waterproofing they couldn't have been waterproofing
Interrogative form
Simple form
could I waterproof? could you waterproof? could he waterproof? could we waterproof? could you waterproof? could they waterproof?
V-ing form
could I be waterproofing? could you be waterproofing? could he be waterproofing? could we be waterproofing? could you be waterproofing? could they be waterproofing?
Perfect
could I have waterproofed? could you have waterproofed? could he have waterproofed? could we have waterproofed? could you have waterproofed? could they have waterproofed?
V-ing perfect
could I have been waterproofing? could you have been waterproofing? could he have been waterproofing? could we have been waterproofing? could you have been waterproofing? could they have been waterproofing?
Interro-negative form
Simple form
couldn't I waterproof? couldn't you waterproof? couldn't he waterproof? couldn't we waterproof? couldn't you waterproof? couldn't they waterproof?
V-ing form
couldn't I be waterproofing? couldn't you be waterproofing? couldn't he be waterproofing? couldn't we be waterproofing? couldn't you be waterproofing? couldn't they be waterproofing?
Perfect
couldn't I have waterproofed? couldn't you have waterproofed? couldn't he have waterproofed? couldn't we have waterproofed? couldn't you have waterproofed? couldn't they have waterproofed?
V-ing perfect
couldn't I have been waterproofing? couldn't you have been waterproofing? couldn't he have been waterproofing? couldn't we have been waterproofing? couldn't you have been waterproofing? couldn't they have been waterproofing?