In this English grammar question on prepositions and tenses, fill in the blank with the most appropriate word in the sentence "Neha has been crying _____ morning."

Introduction / Context:
This question tests your understanding of the correct preposition used with the present perfect continuous tense in English. The sentence is "Neha has been crying _____ morning." Prepositions like "since", "for", "from", and "till" are often confused in time expressions, and competitive exams frequently test the correct pairing of tense and preposition. Here, you need to identify which preposition correctly introduces a point of time in the present perfect continuous construction.

Given Data / Assumptions:

• The sentence is "Neha has been crying _____ morning."
• The tense structure "has been crying" is present perfect continuous.
• The word "morning" is used as a point in time, not a duration.
• The options are from, of, since, and till.

Concept / Approach:
In English grammar, the present perfect continuous tense (has been / have been + verb-ing) is frequently used with "since" and "for". "Since" is used to show the starting point of an action that began in the past and continues into the present. "For" is used to show the duration. In this sentence, "morning" refers to a starting point (this morning), not to a duration like "three hours". Therefore, the correct preposition to use with "has been crying" and "morning" is "since". The other prepositions do not form an idiomatic or grammatically correct expression in this context.

Step-by-Step Solution:
Step 1: Identify the tense: "has been crying" is present perfect continuous, indicating an action that started in the past and is still going on. Step 2: Note that the time expression "morning" functions as a point of time (today's morning) rather than a span of time. Step 3: Recall the rule: use "since" to refer to the starting point of an action (since morning, since 9 am, since Monday). Step 4: Test "Neha has been crying since morning." This sounds correct and natural in standard English. Step 5: Test "Neha has been crying from morning." This is awkward and incomplete; normally we say "from morning till evening". Step 6: Test "Neha has been crying of morning." This is grammatically incorrect. Step 7: Test "Neha has been crying till morning." This suggests the crying stopped at morning and would require a starting point earlier, so it does not match the intended meaning.

Verification / Alternative check:
We can verify by recalling standard phrases commonly used in English: "since morning", "since yesterday", "since childhood", all indicate the starting point of an ongoing action. For example, "I have been studying since morning" and "It has been raining since night". All these follow the same pattern as the sentence given in the question. Grammar books also teach that "since" is used with a point of time and "for" with a period of time. Here, "morning" functions as a point, so "since" is appropriate.

Why Other Options Are Wrong:
"from" usually needs a pair such as "from ... to ..." or "from ... till ...". Using it alone as "crying from morning" sounds incomplete and unnatural. "of" does not express time in this sense and would be grammatically incorrect in "crying of morning". "till" shows the ending point of an action (till evening, till night); it does not indicate when the action started, which is what we need here.

Common Pitfalls:
Learners often confuse "since" and "from" because both can refer to starting points. However, in combination with the present perfect continuous tense, "since" is almost always preferred when we do not explicitly mention the ending point. Another mistake is to insert "from" alone without completing the time range. To avoid this, remember the simple rule: with "has been" or "have been", when you mention the starting time only, use "since". This will help you quickly answer many similar questions in competitive exams.

Final Answer:
The correct preposition is since, so the complete sentence is "Neha has been crying since morning."