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