In the following passage, some of the words have been left out. Read the passage carefully and select the correct option for the given blank. "painters have technical knowledge to paint, but lack to understand nature, __________ they fail to create a masterpiece."

Introduction / Context:
This cloze test focuses on selecting the correct connector that shows a logical relationship between cause and effect. The sentence explains that painters have technical skill but do not understand nature, and as a result they fail to produce masterpieces. Such questions are common in reading comprehension passages to test understanding of logical connectors.

Given Data / Assumptions:

• Sentence fragment: "painters have technical knowledge to paint, but lack to understand nature, __________ they fail to create a masterpiece."
• The first part describes the cause: they lack understanding of nature.
• The second part describes the effect: they fail to create a masterpiece.
• The blank must be filled with a word that signals this cause effect relation.

Concept / Approach:
In English, words like "hence," "therefore," and "so" are used to show that one statement is a result of another. In formal writing, "hence" is common for indicating consequence. The other options, such as "if," "that," or "this," either introduce conditions, clauses, or references and do not naturally link cause and effect in this position.

Step-by-Step Solution:
Step 1: Recognise the structure: cause (lack of understanding) followed by effect (failure to create a masterpiece). Step 2: Choose a connector that means "as a result" or "for this reason." Step 3: Insert "hence" into the sentence: "but lack to understand nature, hence they fail to create a masterpiece." Step 4: Read the full passage to ensure the tone and register match a slightly formal word like "hence." Step 5: Confirm that the flow of ideas is smooth and logically consistent.

Verification / Alternative check:
Test the alternatives. "If they fail to create a masterpiece" would introduce a condition, which is not intended. "That they fail" would need a different sentence structure and sounds awkward after a comma. "This they fail" also feels clumsy and does not express the cause effect connection clearly. "Hence" correctly conveys that failure is the result of lacking understanding.

Why Other Options Are Wrong:

• if: Introduces a conditional clause, which would change the meaning to something like "if they fail," rather than explaining why they fail.
• that: Usually introduces a noun clause and does not work as a stand alone connector in this position.
• this: Functions as a pronoun and would require a different structure; it does not directly express consequence.

Common Pitfalls:
Students sometimes choose "that" or "this" because they are frequently seen in complex sentences, but they forget to check whether these words introduce the right type of clause. In cloze test connectors, always think about the logical relationship: cause, contrast, condition, or addition. Here, the relationship is clearly causal, which points to "hence" as the correct choice.

Final Answer:
The appropriate connector to express the result is hence.