The words that form the independent clause in the sentence "The movie, which we watched yesterday, was hilarious." are: The movie was hilarious.
Explanation:
There are two types of clauses:
Independent clauses: they can stand on their own. That is to say, that they make sense when we read them. There is no need for extra information to understand the meaning.
Dependent clauses: they can not stand on their own. In other words, they depend on another clause, which gives the necessary information to understand the meaning of the dependant clause.
Both types of clauses consist mainly of a subject and a verb, they are separated by commas, or they have subordinating conjunction at the beginning of the clause.
In this case, the clause between commas (which we watched yesterday) is the dependant clause. I can not fully understand the meaning of it when reading only that clause since information is missing. The clause The movie was hilarious is the independent clause because it can stand on its own.
