I could survey you could survey he could survey we could survey you could survey they could survey
V-ing form
I could be surveying you could be surveying he could be surveying we could be surveying you could be surveying they could be surveying
Perfect
I could have surveyed you could have surveyed he could have surveyed we could have surveyed you could have surveyed they could have surveyed
V-ing perfect
I could have been surveying you could have been surveying he could have been surveying we could have been surveying you could have been surveying they could have been surveying
Negation
Simple form
I could not survey you could not survey he could not survey we could not survey you could not survey they could not survey
V-ing form
I could not be surveying you could not be surveying he could not be surveying we could not be surveying you could not be surveying they could not be surveying
Perfect
I could not have surveyed you could not have surveyed he could not have surveyed we could not have surveyed you could not have surveyed they could not have surveyed
V-ing perfect
I could not have been surveying you could not have been surveying he could not have been surveying we could not have been surveying you could not have been surveying they could not have been surveying
Interrogative form
Simple form
could I survey? could you survey? could he survey? could we survey? could you survey? could they survey?
V-ing form
could I be surveying? could you be surveying? could he be surveying? could we be surveying? could you be surveying? could they be surveying?
Perfect
could I have surveyed? could you have surveyed? could he have surveyed? could we have surveyed? could you have surveyed? could they have surveyed?
V-ing perfect
could I have been surveying? could you have been surveying? could he have been surveying? could we have been surveying? could you have been surveying? could they have been surveying?
Interro-negative form
Simple form
could I not survey? could you not survey? could he not survey? could we not survey? could you not survey? could they not survey?
V-ing form
could I not be surveying? could you not be surveying? could he not be surveying? could we not be surveying? could you not be surveying? could they not be surveying?
Perfect
could I not have surveyed? could you not have surveyed? could he not have surveyed? could we not have surveyed? could you not have surveyed? could they not have surveyed?
V-ing perfect
could I not have been surveying? could you not have been surveying? could he not have been surveying? could we not have been surveying? could you not have been surveying? could they not have been surveying?