Answer:
Step-by-step explanation:
In this sentence, we have something that started in the past and is being continued in the present. Therefore, it is a present perfect continuous tense.
It will have -
1. Have/has been
2. verb + -ing
3. Since/for
4. Object
Here as the action is still continuing, we'll use since.
WE HAVE BEEN WATCHING TV SINCE WE HAD DINNER.