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