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