What is the primary purpose of using commas with introductory elements?

• To change the meaning of the sentence

• To add more words

• To make sentences longer

• To ensure clarity and avoid confusion

When should a comma be used after an introductory adverbial phrase?

• Only if the phrase is at the end of a sentence

• If it modifies the entire main clause

• If it contains more than three words

• Only if it starts with 'when'

What is the main clause in the sentence: 'When they earn reward points, customers are more likely to return'?

• 'Customers are more likely to return'

• 'When they earn reward points'

• Both clauses are main clauses

• Neither clause is a main clause

What is the role of a comma after an introductory infinitive?

• To indicate a question

• To separate the infinitive from the main clause

• To add emphasis to the infinitive

• To end the sentence

How does an introductory participial phrase affect sentence clarity?

• It makes the sentence more complex

• It requires a comma to ensure clarity

• It simplifies the sentence

• It is always followed by a verb

In which scenario is a comma optional after a short introductory prepositional phrase?

• When the phrase is less than four words

• When the phrase is at the end of a sentence

• When the phrase contains a verb

• When the phrase is a question

Why is a comma not used if a prepositional phrase is immediately followed by a verb?

• Because it makes the sentence too long

• Because it changes the meaning of the verb

• Because the phrase acts as the subject

• Because it is grammatically incorrect

What is the effect of omitting a comma after a long introductory prepositional phrase in formal writing?

• It may reduce clarity

• It makes the sentence more formal

• It is grammatically incorrect

• It enhances the style of the writing

What distinguishes a non-restrictive a positive phrase from a restrictive one?

• Non-restrictive phrases provide non-essential information

• Restrictive phrases are always followed by a comma

• Restrictive phrases are always at the end

• Non-restrictive phrases are essential to the sentence

When should a comma be used after a non-restrictive a positive phrase?

• Only if it contains more than three words

• When the information is non-essential

• Only if it is at the beginning of a sentence

• Always, regardless of sentence structure