Directions: Select the most appropriate option to substitute the underlined segment in the given sentence. If there is no need to substitute it, select No improvement. Since it falls on the floor, her dog, a black Labrador, gulped the biscuit down.

Explanation

The correct answer is 'Since it fell' Key Points The given phrase is to be replaced with 'Since it fell' In the given sentence there are two clauses the main clause is 'Her dog, a black Labrador, gulped the biscuit down.' and the subordinate clause is 'Since it falls on the floor' As we can see that the main clause's verb is in the past tense the verb is 'gulped' so according to the rule of grammar the subordinate clause should be in the past tense. So we should replace 'falls' with 'fell' So the correct sentence is-Since it fell on the floor, her dog, a black Labrador, gulped the biscuit down.