present
I doubt
You doubt
He doubts
She doubts
It doubts
We doubt
They doubt
past
I doubted
You doubted
He doubted
She doubted
It doubted
We doubted
They doubted
future
I will doubt
You will doubt
He will doubt
She will doubt
It will doubt
We will doubt
They will doubt
conditional
I would doubt
You would doubt
He would doubt
She would doubt
It would doubt
We would doubt
They would doubt