In the following sentence, identify the part that contains a grammatical error: "I have come as soon as the customers leave your shop."

Introduction / Context:
This error spotting question tests your understanding of tense consistency in complex sentences that refer to past actions. The sentence "I have come as soon as the customers leave your shop" sounds unnatural in standard English because it mixes present perfect with a present tense clause where a past tense is expected. To correct it, we must understand how clauses introduced by "as soon as" behave when they refer to completed events in the past.

Given Data / Assumptions:
• The sentence is: "I have come as soon as the customers leave your shop." • Part A: "I have come." • Part B: "as soon as." • Part C: "the customers leave your shop." • The action is clearly completed and refers to a past situation.

Concept / Approach:
When we talk about a completed past action that happened immediately after another past action, we usually use simple past tense in both clauses: "I came as soon as the customers left your shop." Present perfect can also be used with adverbs like just, already, or yet, but it is not combined with a present tense verb that refers to a past time in the same sentence. Therefore the main area to check is the tense of the verb "leave" in the subordinate clause introduced by "as soon as".

Step-by-Step Solution:
1. Identify that the context is past: the speaker is explaining a completed arrival after customers had gone. 2. Recognise that "as soon as" links two actions that occur one immediately after the other. 3. Understand that in such past contexts, both actions are usually in the simple past: "came" and "left". 4. Notice that the sentence uses present perfect "have come" and present tense "leave". 5. Focus on part C, "the customers leave your shop", which reads as if the customers leave habitually rather than in a completed past instance. 6. Conclude that part C should be corrected to "the customers left your shop", which shows a specific past action.

Verification / Alternative check:
Try rewriting the entire sentence in a natural way: "I came as soon as the customers left your shop." This version sounds smooth and grammatically correct and uses simple past in both clauses. You can also adjust the first clause to present perfect if you add a current time reference, for example, "I have come now that the customers have left your shop." In both improved versions, the verb in the subordinate clause about the customers is in the past. This confirms that the error lies in the original use of "leave" in part C.

Why Other Options Are Wrong:
Part A, "I have come", can be acceptable in some contexts, especially if the speaker has just arrived and the focus is on the present result. Part B, "as soon as", is the correct conjunction to indicate immediate succession of actions. Part D, "No error", is incorrect because we have clearly identified a problem in the tense of the third part. Therefore, the only part that must be marked as containing the error is part C, the clause "the customers leave your shop".

Common Pitfalls:
Students sometimes focus too much on the first clause and think that present perfect is always wrong with past time reference, but here the more serious problem is the mismatch between the clauses. Another common mistake is to assume that "as soon as" always attracts present tense even in past contexts, which is not true. The safest method is to imagine how you would naturally say the sentence in conversation about a past event and then see which of the given parts does not match that natural pattern.

Final Answer:
The error is in part C, "the customers leave your shop", which should be "the customers left your shop".