Understanding Sentence Combination and Past Tenses

The question asks us to combine two separate sentences into a single, grammatically correct sentence that accurately reflects the relationship between the two events:

1. Priya reached the station.
2. The bus left before her.

The second sentence tells us that the bus departing happened before Priya arrived at the station. This time relationship between two past events is key to choosing the correct combination.

Analyzing the Options for Combining Sentences

Let's look at each option provided and see how it combines the sentences and whether it correctly represents the sequence of events using appropriate verb tenses.

1. When Priya reached the station, the bus had already left.

   • This sentence uses "reached" (simple past) for Priya's arrival.
   • It uses "had already left" (past perfect) for the bus departing.
   • The past perfect tense ("had left") is used for an action that was completed before another action in the past (Priya reaching the station). This correctly shows that the bus leaving happened before Priya arrived.
   • The conjunction "When" appropriately connects the two events in time.

2. When Priya had reached the station, the bus already left.

   • This sentence uses "had reached" (past perfect) for Priya's arrival.
   • It uses "already left" (simple past) for the bus departing.
   • Using the past perfect for Priya's arrival suggests her arrival happened before another past action, but the second part uses simple past for the bus leaving. This structure incorrectly implies Priya's arrival happened before the bus left, contradicting the original information.

3. Priya reached the station, when the bus already left.

   • This sentence uses "reached" (simple past) for Priya's arrival.
   • It uses "already left" (simple past) for the bus departing.
   • While using simple past for both *can* sometimes indicate sequential actions, the phrasing here is awkward, and using "already" with the simple past after "when" doesn't clearly establish the preceding nature of the bus leaving. The use of past perfect is the standard way to clearly show one past action completed before another.

4. When Priya had reached the station, the bus had already left.

   • This sentence uses "had reached" (past perfect) for Priya's arrival.
   • It uses "had already left" (past perfect) for the bus departing.
   • Using past perfect for both actions implies both were completed before some other point in the past, or incorrectly suggests Priya's arrival also happened before the bus leaving. This does not accurately represent the simple past event of Priya reaching the station occurring after the earlier past event of the bus leaving.

Identifying the Correct Combination

Based on the analysis, option 1 correctly uses the simple past tense for the later action (Priya's arrival) and the past perfect tense for the earlier action (the bus leaving). This structure accurately reflects that the bus had already completed its action of leaving by the time Priya reached the station.

The correct combination is: When Priya reached the station, the bus had already left.

Revision Table: Past Simple vs. Past Perfect

Additional Information: Adverbs like 'Already'

"Already" is often used with the past perfect to emphasize that an action was completed before a specific point in the past or before another past action. In the correct sentence, "the bus had already left" stresses that the departure was finished before Priya's arrival.

Using "already" with the simple past, as seen in options 2 and 3, is less common and can sound incorrect when describing an action completed before another past event in a formal context. The past perfect provides a clearer indication of this preceding action.