In the following sentence, one numbered part may contain a grammatical error, or the sentence may be fully correct. Choose the number of the part that has an error, or choose option (4) for No Error. Sentence: You occasionally stop to admire the intellectual (1) / scenery, or you sometimes retrace your steps (2) / to make sure you had seen everything. (3)

Introduction / Context:
This sentence correction question focuses on tense consistency in English. The sentence describes common habits in a general context, and such habits are usually expressed with the simple present tense. The examiner wants to see whether the learner can recognise that the final clause shifts unnecessarily to a past perfect tense, which is not appropriate here.

Given Data / Assumptions:

• The sentence is divided into three numbered parts, with option (4) reserved for No Error.
• The main subject you refers to a generic person and is used in the sense of one.
• The first two parts use simple present tense verbs stop and retrace.
• The third part contains the verb phrase had seen, which is in the past perfect tense.

Concept / Approach:
The key concept tested is tense agreement within a single sentence about general behaviour. When we describe habitual actions or general truths, we normally use the simple present tense: you stop, you retrace, you make sure you have seen everything. The past perfect tense had seen is reserved for describing an action completed before another past action. In this sentence, there is no earlier past action that justifies the use of past perfect. Therefore, the third part contains the error, and it should read to make sure you have seen everything or to make sure you see everything.

Step-by-Step Solution:
Step 1: Observe that the sentence as a whole talks about what you occasionally or sometimes do in general, not about a particular past event.Step 2: Examine part (1): You occasionally stop to admire the intellectual. This is a shortened way of saying intellectual scenery, which is completed in part (2). There is no tense problem here.Step 3: Examine part (2): scenery, or you sometimes retrace your steps. Again, this part uses the simple present tense and matches the general habit context.Step 4: Examine part (3): to make sure you had seen everything. The use of had seen introduces past perfect tense, which normally requires a clear reference to another past action.Step 5: Notice that no such earlier past action is mentioned. The sentence is not a narrative about a specific time but a description of regular behaviour.Step 6: Conclude that part (3) contains the grammatical error because the tense is inconsistent with the rest of the sentence.

Verification / Alternative check:
To verify the answer, try correcting the third segment. If we change the phrase to make sure you have seen everything, the full sentence becomes: You occasionally stop to admire the intellectual scenery, or you sometimes retrace your steps to make sure you have seen everything. Now the actions stop, retrace, and have seen all align around a general present context. If we wanted a fully simple present version, we could also say to make sure you see everything. Either corrected form highlights that had seen was the wrong tense choice, confirming that segment (3) is the one with an error.

Why Other Options Are Wrong:
Option 1: Part (1) is grammatically sound, and the phrase You occasionally stop to admire the intellectual is correctly continued in the next part as intellectual scenery.Option 2: Part (2) correctly uses sometimes retrace in the simple present tense to describe a habitual action, which matches the rest of the sentence.Option 4: The sentence is not completely correct because the tense in part (3) is inappropriate, so the No Error choice cannot be right.

Common Pitfalls:
A common mistake in such questions is to focus on vocabulary such as intellectual scenery and ignore the underlying tense structure. Another pitfall is to assume that had seen sounds more sophisticated than have seen and therefore must be correct, even though tense choice should always follow the logic of time reference, not the apparent complexity of the form. Learners should train themselves to read each part while asking whether the time frame is consistent throughout the sentence.

Final Answer:
The tense inconsistency appears in the third segment using had seen, so the correct option is 3.