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