In the following question, choose the alternative that best improves the bracketed part of the sentence. In case no improvement is needed, select “no improvement”. Sentence: As long as we are in this historical city, let us spend our time (doing sightseeing).

Introduction / Context:
This sentence improvement question tests your understanding of correct verb patterns in English, especially after the verb spend when it refers to time. The sentence describes how people should use their time while they are in a historical city. The phrase doing sightseeing sounds awkward and is not the most natural expression in standard English. You need to select the option that gives the sentence a smooth and grammatically correct structure.

Given Data / Assumptions:

• Original sentence: As long as we are in this historical city, let us spend our time (doing sightseeing).
• We focus on the phrase after spend our time.
• Options: to sightsee, sightsee, sightseeing, no improvement.
• We assume the intended meaning is to use our time by visiting places of interest.

Concept / Approach:
In English, after spend (time), the most natural construction is spend time doing something or spend time on something. However, with the noun sightseeing, the common phrase becomes spend time sightseeing. The gerund sightseeing acts like a noun here. The phrase doing sightseeing is grammatically possible but clumsy and not idiomatic. Therefore, the bracketed part should be replaced with sightseeing so that the sentence reads: let us spend our time sightseeing.

Step-by-Step Solution:
Step 1: Identify the key structure: spend our time + activity. Step 2: Recall common collocations: spend time reading, spend time studying, spend time sightseeing. Step 3: Examine option c, sightseeing, and substitute it into the sentence: let us spend our time sightseeing. This sounds natural and correct. Step 4: Examine option a, to sightsee. The phrase spend our time to sightsee is unusual; infinitives are not commonly used after spend time in this way. Step 5: Examine option b, sightsee. The form spend our time sightsee is grammatically wrong because sightsee is the base verb and needs to be in the -ing form after spend. Step 6: Examine option d, no improvement, and notice that doing sightseeing is wordy and not standard usage. Step 7: Conclude that sightseeing is the best replacement.

Verification / Alternative check:
Compare with similar structures: Let us spend our time shopping, Let us spend our time exploring museums, and Let us spend our time sightseeing. All of these use the -ing form as a noun-like activity. The version with doing sightseeing is rarely used by native speakers and sounds learner-like. Grammar references also show spend time -ing as a standard pattern, confirming that sightseeing fits correctly after spend our time.

Why Other Options Are Wrong:
To sightsee (option a) is not the usual complement of spend time; while infinitives are common after some verbs, spend time to sightsee is not idiomatic. Sightsee (option b) must change to sightseeing to follow spend time correctly. No improvement (option d) is incorrect because the current phrase is clumsy and not the best form taught for exams. Since a better and more idiomatic alternative is given, we should not choose no improvement.

Common Pitfalls:
Candidates sometimes accept any grammatically possible phrase and overlook natural usage. Others may be misled by the verb sightsee and think that to sightsee sounds formal or correct. In sentence improvement questions, you must look for the most idiomatic and concise option, especially when dealing with common collocations like spend time sightseeing. Remember that spend time + -ing is a reliable pattern for many similar questions.

Final Answer:
The correct improvement is: As long as we are in this historical city, let us spend our time sightseeing.