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