Sentence improvement — Select the correct present perfect with ‘‘since’’ and a time expression: refine ‘‘We had nothing to eat since 8 o'clock, this morning.’’ for precise aspect and punctuation.

Given data
Original: ‘‘We had nothing to eat since 8 o'clock, this morning.’’

Concept/Approach
Use the present perfect with ‘‘since + specific time’’ to connect past start time to the present: ‘‘have had nothing … since 8 o'clock this morning.’’ Also, avoid the unnecessary comma before ‘‘this morning’’.

Option analysis
have had nothing — Correct tense and aspect for a continuing state up to now.has had nothing — Subject–verb disagreement (‘‘we’’ is plural).did have nothing — Double negative flavor and wrong tense for ‘‘since’’ duration.No improvement — Keeps wrong past tense with ‘‘since’’.had nothing — Simple past contradicts ‘‘since …’’ duration.

Verification/Alternative
Model: ‘‘We have had nothing to eat since 7 a.m.’’

Common pitfalls
Using past tenses with ‘‘since’’ when the action/state still holds; inserting commas where none are needed.

Final Answer
have had nothing