Adverbs of time (negative present perfect) “The waiter hasn't brought the coffee ______; I've been here an hour already.” Fill in the blank with the correct adverb.

Given data

• Tense: Present perfect negative (“hasn't brought”).
• Meaning: An expected action has not happened up to now.

Concept/Approach
Yet is used in negative statements and questions to indicate “up to the present.”

Option analysis
yet — correct with present perfect negatives: “hasn't … yet.”still — typically before the verb (“still hasn't brought”), not after the clause.till — a preposition/conjunction, not idiomatic here.up — incomplete phrase; would need “up to now.”

Common pitfalls
Placing “still” at the end of the sentence; correct position is before the auxiliary.

Final Answer
yet