English verb conjugation
COULD APPEND

Regular verb: append - appended - appended

Affirmation

Simple form	V-ing form
I could append you could append he could append we could append you could append they could append	I could be appending you could be appending he could be appending we could be appending you could be appending they could be appending
Perfect	V-ing perfect
I could have appended you could have appended he could have appended we could have appended you could have appended they could have appended	I could have been appending you could have been appending he could have been appending we could have been appending you could have been appending they could have been appending

Negation

Simple form	V-ing form
I couldn't append you couldn't append he couldn't append we couldn't append you couldn't append they couldn't append	I couldn't be appending you couldn't be appending he couldn't be appending we couldn't be appending you couldn't be appending they couldn't be appending
Perfect	V-ing perfect
I couldn't have appended you couldn't have appended he couldn't have appended we couldn't have appended you couldn't have appended they couldn't have appended	I couldn't have been appending you couldn't have been appending he couldn't have been appending we couldn't have been appending you couldn't have been appending they couldn't have been appending

Interrogative form

Simple form	V-ing form
could I append? could you append? could he append? could we append? could you append? could they append?	could I be appending? could you be appending? could he be appending? could we be appending? could you be appending? could they be appending?
Perfect	V-ing perfect
could I have appended? could you have appended? could he have appended? could we have appended? could you have appended? could they have appended?	could I have been appending? could you have been appending? could he have been appending? could we have been appending? could you have been appending? could they have been appending?

Interro-negative form

Simple form	V-ing form
couldn't I append? couldn't you append? couldn't he append? couldn't we append? couldn't you append? couldn't they append?	couldn't I be appending? couldn't you be appending? couldn't he be appending? couldn't we be appending? couldn't you be appending? couldn't they be appending?
Perfect	V-ing perfect
couldn't I have appended? couldn't you have appended? couldn't he have appended? couldn't we have appended? couldn't you have appended? couldn't they have appended?	couldn't I have been appending? couldn't you have been appending? couldn't he have been appending? couldn't we have been appending? couldn't you have been appending? couldn't they have been appending?