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