I observe you observe he observes we observe you observe they observe
Present continuous
I am observing you are observing he is observing we are observing you are observing they are observing
Preterite
I observed you observed he observed we observed you observed they observed
Preterite continuous
I was observing you were observing he was observing we were observing you were observing they were observing
Present perfect
I have observed you have observed he has observed we have observed you have observed they have observed
Present perfect continuous
I have been observing you have been observing he has been observing we have been observing you have been observing they have been observing
Pluperfect
I had observed you had observed he had observed we had observed you had observed they had observed
Pluperfect continuous
I had been observing you had been observing he had been observing we had been observing you had been observing they had been observing
Future
I will observe you will observe he will observe we will observe you will observe they will observe
Future continuous
I will be observing you will be observing he will be observing we will be observing you will be observing they will be observing
Future perfect
I will have observed you will have observed he will have observed we will have observed you will have observed they will have observed
Future perfect continuous
I will have been observing you will have been observing he will have been observing we will have been observing you will have been observing they will have been observing
Conditional
Present
I would observe you would observe he would observe we would observe you would observe they would observe
Present continuous
I would be observing you would be observing he would be observing we would be observing you would be observing they would be observing
Past
I would have observed you would have observed he would have observed we would have observed you would have observed they would have observed
Past continuous
I would have been observing you would have been observing he would have been observing we would have been observing you would have been observing they would have been observing