Answer: The two errors in a sentence are Change sisters to sisters' and Change singles to singles.
Explanation: What is an error in a sentence?
A sentence fragment is a specific grammar mistake that occurs when a collection of words are put together but do not fully represent the content of the phrase.
It happens when a phrase or dependent clause (subordinate clause) can stand on its own as though it were a whole sentence. Another example is when a sentence fragment is presented as a complete sentence.
When permitted to stand alone, a phrase—a group of two, three, or more words that do not contain a subject or verb—becomes a sentence fragment. Even though a dependent clause has a subject and verb, the same thing occurs.
Therefore, The two errors in the sentence are Change sisters to sisters' and Change singles to singles.