Concept:
Sentences are classified structurally into three main types based on their clause combinations:
• Simple Sentence: Contains exactly one independent clause with a subject and a predicate.
• Compound Sentence: Contains two or more independent clauses joined together by coordinating conjunctions (FANBOYS: for, and, nor, but, or, yet, so).
• Complex Sentence: Contains exactly one principal independent clause and at least one dependent (subordinate) clause, joined via a subordinating conjunction or relative pronoun (e.g., which, that, who, because, although).
Step 1: Deconstruct the original sentence structure.
The prompt sentence is: "My brother gave me a watch and I have lost it."
Let us separate the clauses:
• *My brother gave me a watch* (Independent Clause)
• *I have lost it* (Independent Clause)
These clauses are linked by the coordinating conjunction 'and', making the source text a compound sentence. Our goal is to convert it into a complex sentence without altering the meaning.
Step 2: Convert the compound layout into a main and subordinate clause pair.
To transform this into a complex structure, we can convert one of these independent statements into an adjective (relative) clause that describes the object noun ("the watch").
• Principal Clause: I have lost the watch
• Subordinate Adjective Clause: which my brother gave me
Here, "which my brother gave me" cannot stand alone as a complete sentence; it is dependent on the main clause and is linked using the relative pronoun 'which'. This fulfills the structural definition of a complex sentence.
Step 3: Evaluate why the other options are incorrect.
Let us inspect the alternative choices to ensure accuracy:
• (B) My brother gave me a watch, but I have lost it: The clauses are joined by 'but', which is a coordinating conjunction. This keeps the sentence structure compound, not complex.
• (C) Since my brother gave me a watch, I lost it: The subordinating conjunction 'since' implies a false cause-and-effect relationship, suggesting that the brother's gift was the direct cause of the loss. This distorts the original meaning.
• (D) I lost the watch that was given to me by my brother: While this is a complex sentence, it unnecessarily introduces passive construction ("that was given to me by..."), making it less direct than option (A), which retains the active profile of the original clauses perfectly.
Therefore, option (A) is the most accurate and natural complex presentation.