Transformation of Sentences

At the ringing of the bell, the students rushed out.

Step 1: Identify the complex structure - The sentence has a dependent clause 'When the bell rang' and main clause 'the students rushed out'. Step 2: Convert dependent clause to phrase - Change 'When the bell rang' to the prepositional phrase 'At the ringing of the bell'. Step 3: Maintain meaning - The time relationship is preserved through the preposition 'at'. Step 4: Check other options - Options A and D create compound sentences, Option C remains complex. Step 5: Verify simple structure - The correct answer has one main clause with a prepositional phrase.

Noun clause

Step 1: Identify the function - The clause 'whoever comes first' acts as a noun in the sentence. Step 2: Check the beginning word - 'Whoever' is a typical noun clause starter, along with 'what', 'that', 'where', etc. Step 3: Test substitution - You can replace this clause with a noun like 'the person' or 'someone'. Step 4: Eliminate other options - Adjective clauses modify nouns, adverb clauses modify verbs/adjectives, independent clauses stand alone. Step 5: Confirm noun function - Noun clauses can serve as subjects, objects, or complements in sentences.

although

Step 1: Identify the original relationship - 'But' shows contrast between being rich and being unhappy. Step 2: Choose subordinating conjunction - 'Although' is a subordinating conjunction that expresses the same contrasting relationship. Step 3: Create complex structure - 'Although he is rich, he is unhappy' has one dependent and one independent clause. Step 4: Check other options - 'And', 'or', and 'so' are coordinating conjunctions that maintain compound structure. Step 5: Verify transformation - The subordinating conjunction creates the required complex sentence structure.

Complex sentence

Step 1: Identify the main clause - 'The book is very interesting' is the independent clause. Step 2: Find the dependent clause - 'that I bought yesterday' is a dependent clause modifying 'book'. Step 3: Recognize the subordinating word - 'That' introduces the dependent adjective clause. Step 4: Apply definition - A complex sentence has one independent clause and one or more dependent clauses. Step 5: Eliminate other options - Simple sentences have one clause, compound sentences have multiple independent clauses, compound-complex has both features.