In the following question on English idioms, choose the alternative which best expresses the meaning of the expression Turn over a new leaf, often used to describe a positive change in behaviour.

Introduction / Context:
This idiom question examines your understanding of the common English expression Turn over a new leaf. This phrase often appears in stories, moral lessons, and conversations about self improvement. It does not literally refer to the leaf of a plant, but to a page or leaf in a book, and symbolises starting a fresh chapter in life by giving up bad habits and adopting better behaviour.

Given Data / Assumptions:

• Idiom: Turn over a new leaf.
• Options describe behaviour change, reading activity, physical movement, and a new job.
• You must choose the option that best captures the accepted figurative meaning.
• The focus is on moral or behavioural improvement, not simply changing tasks.

Concept / Approach:
Turn over a new leaf means to make a fresh start, especially by changing ones conduct or habits for the better. The imagery is of turning a page in a book to begin writing a better story. The correct answer should mention positive change in behaviour, not just performing a new action. The options that mention reading between pages, doing a somersault, or starting a new job are not connected with moral improvement and therefore do not match the idiom.

Step-by-Step Solution:
Step 1: Recall that the idiom is often used when someone decides to stop bad habits and live more responsibly. Step 2: Examine option a, change ones behaviour for the better. This directly refers to behavioural improvement and a fresh start. Step 3: Examine option b, read between the pages of a book. This describes an action related to reading and not to personal change. Step 4: Examine option c, do a somersault, which refers to a physical movement and is unrelated to moral choices. Step 5: Examine option d, do a new job, which might be part of a new start but does not capture the emphasis on better behaviour. Step 6: Conclude that option a is the only one that reflects the figurative meaning of the idiom.

Verification / Alternative check:
Consider example sentences such as After failing his exams, he decided to turn over a new leaf and study seriously. Here the idiom clearly refers to changing habits, not to reading or doing gymnastics. If we replace it with change his behaviour for the better, the sentence keeps the same meaning. Replacing it with start a new job or do a somersault would make the sentence illogical. This confirms that option a is the best match.

Why Other Options Are Wrong:
Read between the pages of a book: Talks about a literal reading activity and has nothing to do with self improvement.
Do a somersault: Describes a physical action and does not suggest any moral or behavioural change.
Do a new job: Refers to employment, which can change even when behaviour remains the same, so it does not express the deeper idea of turning over a new leaf.

Common Pitfalls:
Some learners focus on individual words like leaf and imagine only plants or books. Others think of any kind of change as a new leaf. To avoid confusion, remember that idioms often carry a moral or emotional message. Turn over a new leaf belongs to the group of expressions that talk about becoming more responsible, such as mend ones ways or make a fresh start. Connecting the idiom to this theme will help you recall the correct meaning quickly in examination conditions.

Final Answer:
The idiom Turn over a new leaf means change ones behaviour for the better, so option a is correct.