Question

How could you combine the following two sentences into a complex sentence with a dependent adjectival clause? The boy wore a green coat. He carried his sister home.

Answer 1

A complex sentence contains one independent clause and at least one dependent clause. Here, in your example, there are two simple independent clauses which you need to merge using a dependent adjectival clause in order to make one complex sentence. Here is how to do it:
The boy who wore a green coat carried his sister home.