Answer:
Your answer would be that the independent clause in the sentence is the following one: "we are not eating on the patio".
Step-by-step explanation:
The sentence above is a complex sentence. A complex sentence has one independent clause and at least one dependent clause. An independent clause can stand alone as a sentence because it represents a complete thought; it contains a subject and a predicate and does not depend on any other clause to complete its meaning (1). On the contrary, dependent clauses depend on the meain sentence to complete their meaning. 2 cannot stand alone as a sentence because it is a dependent clause. That is why the sentence is grammatically incorrect.
1) We are not eating on the patio
2) *Because it is raining too hard