I could shelter you could shelter she could shelter we could shelter you could shelter they could shelter
V-ing form
I could be sheltering you could be sheltering she could be sheltering we could be sheltering you could be sheltering they could be sheltering
Perfect
I could have sheltered you could have sheltered she could have sheltered we could have sheltered you could have sheltered they could have sheltered
V-ing perfect
I could have been sheltering you could have been sheltering she could have been sheltering we could have been sheltering you could have been sheltering they could have been sheltering
Negation
Simple form
I couldn't shelter you couldn't shelter she couldn't shelter we couldn't shelter you couldn't shelter they couldn't shelter
V-ing form
I couldn't be sheltering you couldn't be sheltering she couldn't be sheltering we couldn't be sheltering you couldn't be sheltering they couldn't be sheltering
Perfect
I couldn't have sheltered you couldn't have sheltered she couldn't have sheltered we couldn't have sheltered you couldn't have sheltered they couldn't have sheltered
V-ing perfect
I couldn't have been sheltering you couldn't have been sheltering she couldn't have been sheltering we couldn't have been sheltering you couldn't have been sheltering they couldn't have been sheltering
Interrogative form
Simple form
could I shelter? could you shelter? could she shelter? could we shelter? could you shelter? could they shelter?
V-ing form
could I be sheltering? could you be sheltering? could she be sheltering? could we be sheltering? could you be sheltering? could they be sheltering?
Perfect
could I have sheltered? could you have sheltered? could she have sheltered? could we have sheltered? could you have sheltered? could they have sheltered?
V-ing perfect
could I have been sheltering? could you have been sheltering? could she have been sheltering? could we have been sheltering? could you have been sheltering? could they have been sheltering?
Interro-negative form
Simple form
couldn't I shelter? couldn't you shelter? couldn't she shelter? couldn't we shelter? couldn't you shelter? couldn't they shelter?
V-ing form
couldn't I be sheltering? couldn't you be sheltering? couldn't she be sheltering? couldn't we be sheltering? couldn't you be sheltering? couldn't they be sheltering?
Perfect
couldn't I have sheltered? couldn't you have sheltered? couldn't she have sheltered? couldn't we have sheltered? couldn't you have sheltered? couldn't they have sheltered?
V-ing perfect
couldn't I have been sheltering? couldn't you have been sheltering? couldn't she have been sheltering? couldn't we have been sheltering? couldn't you have been sheltering? couldn't they have been sheltering?