Answer:
(2) On reaching the kite festival.
Explanation:
First, to answer a question about sentence fragments, you must know the meaning of a sentence fragment. A sentence fragment starts with a capital letter and ends with a quotation mark just like a regular sentence. However, it does not have an independent clause.
An independent clause is a part of a sentence that has at least one subject and action. Independent clauses work on their own. Sometimes you can add a dependent clause to an independent clause. Dependent clauses are usually background information that are added on. Dependent clauses need independent clauses to work; without independent clauses, dependent clauses become a sentence fragment and they don't make sense.
For example, this is an independent clause: "Jack ate an apple." Now, let's add a dependent clause to this sentence: "Jack ate an apple with his eyes closed<em>.</em>" Now, let's have the dependent clause by itself: "With his eyes closed." The dependent clause on its own does not have a subject. Who is "his?" We don't know. What did he do with his eyes closed? We don't know. This is called a sentence fragment. It is a broken part of a sentence.
Now, let's get back to the question. Which sentence is a sentence fragment? Well, now this is pretty easy. You look at each sentence and look to see if it has a subject and an action/thought. If it doesn't have a subject or an action, then it is a sentence fragment. Here are the answers:
1. This makes sense. Steve(subject) went to a kite festival last summer(action).
2. This doesn't make sense. What is "on reaching?" Who reached the kite festival? Who planned on reaching the kite festival? Who decided on reaching the kite festival? This is a sentence fragment.
3. This has a subject(he) and has an action/thought(amazed by the kites). This makes sense.
4. This has a subject(he) and an action/thought(realized that flying a kite needs skill).
Only one of these sentences does not have a subject, which is absolutely required in a sentence: 2. It doesn't even have a complete action. It doesn't say what they did.<em> </em>This is actually a split sentence from 3. If you read answers 2 and 3 and replacing the period in between them with a comma, then the sentence makes sense.
