No, it is not complex. "After the rain ended..." contains a verb and a subject: rain & ended. "After the rain" contains no verb. It is a prepositional phrase, modifying the verb "went" (an adverb phrase).
A complex sentence contains a dependent clause (which cannot stand on it's own as a complete thought or sentence) and an independent clause. "After the rain ended" is a dependent clause. "I went to the park" is an independent clause (it can stand on its own). Both clauses, dependent and independent, contain a subject and verb. An adjective or adverb phrase do not contain both subject and verb.
We're studying different types of sentences. I think that the example in our notes is wrong.
Example#1: After the rain, I went to the park.
Ans: Labeled as simple. But, I think it should be complex.
There's a similar sentence that was done in class and it was labeled as complex - After the rain ended, I went to the park. So, that's why I think Example#1 should be complex as well.
2 answers
Thanks!!