In English idioms and phrases, select the option that best expresses the meaning of the expression "Mend your ways".

Introduction / Context:
The expression "mend your ways" is a common idiom in English. It is often used by elders, teachers, or authority figures when advising someone to correct bad habits or improper conduct. Such idioms frequently appear in English sections of competitive exams, where understanding their figurative meaning is crucial for scoring well.

Given Data / Assumptions:

• Idiom: "Mend your ways".
• Task: Choose the best meaning that matches this idiom.
• Options refer to being happy with behaviour, sad with behaviour, destroying behaviour, or improving behaviour.
• The context is usually an advice or warning to someone who behaves wrongly or irresponsibly.

Concept / Approach:
The verb "mend" literally means to repair something that is broken or damaged, such as clothes or machines. In the idiom "mend your ways", the word "ways" refers to a person's habits or behaviour. Therefore, the figurative meaning is to correct or improve one's behaviour, especially after being warned or criticised. The correct option must capture this idea of positive change and improvement, not just an emotional state like happiness or sadness.

Step-by-Step Solution:
Step 1: Think of typical sentences: "You had better mend your ways or you will be punished." Here, the speaker wants the person to correct bad behaviour. Step 2: Check which option directly expresses the idea of correction and improvement. Step 3: "Happy with one's behaviour" describes a feeling, not a change or correction, so it is not the right meaning. Step 4: "Sad with one's behaviour" again describes an emotional reaction rather than a change in conduct. Step 5: "Destroy one's behaviour" does not make sense as a natural phrase and does not reflect the idea of improvement. Step 6: "Improve one's behaviour" clearly matches the idea of repairing or correcting one's ways.

Verification / Alternative check:
Look at similar idiomatic expressions and how they are used in moral or disciplinary contexts. When a parent says, "It is time for you to mend your ways", they are not saying that the person should be happy or sad, but that they should change for the better. Grammar reference books and dictionaries explain "mend one's ways" as "to improve one's conduct or habits, especially after criticism or a warning". This confirms that "improve one's behaviour" is the closest and most accurate option.

Why Other Options Are Wrong:

• Happy with one's behaviour: Indicates satisfaction with current behaviour, which is opposite to the need to change or mend anything.
• Sad with one's behaviour: Shows regret or unhappiness, but does not itself mean changing or improving behaviour.
• Destroy one's behaviour: Is not a standard English phrase and does not relate to the idea of positive change. It is vague and incorrect.

Common Pitfalls:
Students may focus too much on the word "mend" and think only of physical repair, or they may be distracted by emotional words like "happy" and "sad" in the options. Remember that in idioms, words often have extended figurative meanings. The key skill is to recall or infer the meaning based on how the expression is used in real life, not by translating each word literally. Regular reading and exposure to idiomatic expressions will help avoid such mistakes in exams.

Final Answer:
The idiom "Mend your ways" means improve one's behaviour.