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