In the following sentence, the bracketed part needs improvement. Out of the four alternatives, select the option that best improves the sentence. In case no improvement is needed, select "No improvement". She (had to) four previous solo shows.

Introduction / Context:
This sentence improvement question focuses on correct tense and aspect in English, particularly the present perfect tense used to describe experiences up to the present. The sentence is talking about the number of solo shows she has done in her life up to now. The bracketed phrase "had to" is incorrect here and must be replaced with a form that properly connects "She" with "four previous solo shows".

Given Data / Assumptions:

• Original sentence: "She (had to) four previous solo shows."
• The intended meaning is likely that she has already given or organised four solo shows in the past.
• Options: has, has had, has been, no improvement.
• "Four previous solo shows" functions as the object of a verb describing her experience.

Concept / Approach:
To talk about life experiences that have occurred at unspecified times before now, we usually use the present perfect tense: "has had", "has done", "has given". The correct structure is "She has had four previous solo shows", where "has had" is the present perfect of "have" in the sense of "experience" or "hold". The phrase "had to" is a modal construction meaning "was obliged to", which does not fit this context and is also incomplete without a following verb. Thus, the best improvement is "has had".

Step-by-Step Solution:
Step 1: Interpret the sentence: it wants to convey that, before now, she has already done four solo shows.Step 2: Recognise that "had to" usually means "was required to" or "was compelled to", as in "She had to leave early", which does not match the idea of counting past shows.Step 3: Try option A: "She has four previous solo shows." This sounds awkward because we normally say "has given" or "has had" when talking about having performed shows.Step 4: Try option B: "She has had four previous solo shows." This clearly indicates her experience of having done four shows so far.Step 5: Try option C: "She has been four previous solo shows." This is ungrammatical. Option D, "no improvement", would keep the incorrect "had to". Therefore, "has had" is the correct choice.

Verification / Alternative check:
Compare with similar sentences: "He has had three major exhibitions", "She has had several promotions", "The company has had two product launches this year." In each case, "has had" emphasises completed experiences in the recent past relevant to the present. Replacing "had to" with "has had" in the question sentence produces the same pattern: "She has had four previous solo shows", which fits idiomatic English and exam standards.

Why Other Options Are Wrong:
Option A, "has", would give "She has four previous solo shows", which reads as if she currently possesses the shows as objects, rather than having performed them in the past. Option C, "has been", is used with roles or states ("She has been a teacher"), not with direct objects like "four previous solo shows". Option D, "no improvement", cannot be right because "had to" requires another verb ("had to perform", "had to attend") and does not directly link to "four previous solo shows". Only "has had" correctly expresses her completed experience.

Common Pitfalls:
Some candidates may be confused by the similarity between "had to" and "has had" and may not notice that "had to" indicates obligation, not experience. Others might think "has" is enough, without realising that it changes the sense from "experienced" to "possesses". To avoid such mistakes, pay attention to the overall meaning of the sentence: here, it is about how many solo shows she has already done, which naturally calls for the present perfect "has had".

Final Answer:
The best improvement is: "She has had four previous solo shows."