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