Answer:
The sentence above could be rewritten as follows: Dennis washed his hands. They were muddy.
Explanation:
A complex sentence has one independent clause and at least one dependent clause. An independent clause, unlike a dependent one, can stand alone as a sentence because it represents a complete thought (a). A fails to stand alone as a sentence because it does not represent a complete idea.
When you separate the clauses in two different simple sentences, both of them become independent (b, c) and can therefore stand alone as a sentence.
a) *Because they were muddy
b) Dennis washed his hands
c) They were muddy
