Grammar: Preposition Use with Time References

The sentence "She hasn't called me ______ Monday" requires a preposition that connects the action (or lack thereof) to a specific starting point in time. The verb phrase "hasn't called" is in the present perfect tense, which is often used to talk about actions that started in the past and continue to the present, or have relevance to the present.

Choosing the Correct Preposition

Let's analyze the role of each preposition:

• Since: This preposition is used to indicate the starting point of a period. When used with the present perfect tense, it means the action has been happening (or not happening) from that specific point until now. Example: "I haven't seen him since last year." In our sentence, "She hasn't called me since Monday" correctly implies that the period of not calling started on Monday and continues to the present moment.
• For: This preposition is used to indicate a duration or period of time, not a specific starting point. Example: "I haven't called her for three days." Using "for Monday" would be incorrect as Monday is a specific point, not a duration.
• On: This preposition is typically used for specific days or dates when an action occurs. Example: "She called me on Monday." While grammatically sound in other contexts, using "on" with "hasn't called" and the implied continuation to the present isn't standard for this meaning. It doesn't fit the pattern of indicating a starting point for an ongoing state of 'not calling'.
• At: This preposition is used for specific clock times, not days. Example: "She called me at 9 AM." It is unsuitable for referring to a day like Monday in this context.

Sentence Completion Analysis

Considering the structure and tense of the sentence, "since" is the most appropriate preposition to indicate that the lack of a call began on Monday and has continued up to the present time.

Therefore, the completed sentence reads: "She hasn't called me since Monday."