ArticleslgStudy

biology

Greenridge Crescent twin killings

Greenridge Crescent twin killings is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Greenridge Crescent twin killings rather than just read about it. In short: On 21 January 2022, at a playground in Greenridge Crescent, located in Singapore's Upper Bukit Timah, 11-year-old twin brothers Ethan Yap E Chern (Chinese: 叶育成; pinyin: Yè Yùchéng) and Aston Yap Kai Shern (Chinese: 叶凯胜; pinyin: Yè Kǎishèng), who were both diagnosed with autism, were murdered by their 48-year-old father Xavier Yap Jung Houn (Chinese: 叶俊宏; pinyin: Yè Jùnhóng). Yap strangled them both to death before a…

Key takeaways

  • Greenridge Crescent twin killings belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Greenridge Crescent twin killings to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Greenridge Crescent twin killings from memory before moving on to harder problems.

Reference excerpt

On 21 January 2022, at a playground in Greenridge Crescent, located in Singapore's Upper Bukit Timah, 11-year-old twin brothers Ethan Yap E Chern (Chinese: 叶育成; pinyin: Yè Yùchéng) and Aston Yap Kai Shern (Chinese: 叶凯胜; pinyin: Yè Kǎishèng), who were both diagnosed with autism, were murdered by their 48-year-old father Xavier Yap Jung Houn (Chinese: 叶俊宏; pinyin: Yè Jùnhóng). Yap strangled them both to death before attempting suicide. Yap was charged with the double murder, which shocked the nation at the time. Yap, whose murder charges were reduced due to clinical depression, was reported to have killed the boys due to his suicidal thoughts and his belief that his sons would be neglected and unloved by their mother upon his death, and wanted to kill the twins so they would not be burdens to his wife. Yap was sentenced to 14 years' imprisonment in August 2023, after he pleaded guilty to two counts of manslaughter at the High Court.

Background Twins Ethan Yap E Chern and Aston Yap Kai Shern were born on 14 October 2010 to parents Xavier Yap Jung Houn and Anna Seah Puay Hiang, the latter who had a daughter from a previous marriage who lived with the Yaps. Yap, a university graduate who formerly worked as a manager at the Ministry of Defence, had once studied for a doctorate in England. When both Ethan and Aston were two years old, Yap and his wife suspected that the brothers were autistic after noticing certain behavioral signs. In May 2017, at the age of six, the boys were formally diagnosed with global developmental delay and autism spectrum disorder. According to sources, Seah was unable to accept the boys' condition and, despite the doctor's recommendation to enroll the boys in a special education school, enrolled the boys at age nine in Primary 1 at a mainstream primary school located in the Eng Kong estate area while they were still non-verbal. The boys encountered learning difficulties throughout their schooling, so the boys' mother and maid would each accompany one child to classes. Whenever the mother was unavailable, one of the twins would not be present for school. Reportedly, Yap's wife did not allow her husband to have a say in decisions on which school the boys should attend, or their school activities. It was reported that Yap had a good relationship with his sons. Yap would help the brothers to prepare their daily necessities and gave them whatever they wanted, and he would not resort to physical force when he disciplined the twins. Yap also played a more major role in their studies and often made time to spend with them after they enrolled in primary school. However, in 2019 or 2020, Yap became increasingly concerned about his sons' welfare. In 2021, Yap's wife, who allegedly had an affair, began to grow more prone to anger and allegedly became more abusive towards the twins, which only added to his concerns. In December 2021, Yap began to harbour suicidal thoughts, and even bought an ice pick with plans to take his own life. At the start of 2022, the boys were about to be assessed for their suitability to remain in their mainstream primary school, and this turn of events caused Yap's wife to become more depressed and infuriated at her sons. Assuming this was a sign that his wife had given up on the boys, Yap began harbouring serious thoughts of killing his sons before he committed suicide, so as to unburden his wife. Yap also feared for his sons, concerned that they would become ostracized should he and his wife die one day, and which became another factor behind his motive of murdering his sons on 21 January 2022.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Greenridge Crescent twin killings

Start with the simplest possible case. Write down what Greenridge Crescent twin killings claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Greenridge Crescent twin killings before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Greenridge Crescent twin killings ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Greenridge Crescent twin killings

In research
Greenridge Crescent twin killings appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Greenridge Crescent twin killings in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Greenridge Crescent twin killings is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2022 in Singapore, 2022 murders in Singapore, Child filicides, so understanding it makes those chapters shorter.
In everyday life
Look for Greenridge Crescent twin killings outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Greenridge Crescent twin killings” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Greenridge Crescent twin killings in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Greenridge Crescent twin killings means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Greenridge Crescent twin killings out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Greenridge Crescent twin killings in simple terms?

On 21 January 2022, at a playground in Greenridge Crescent, located in Singapore's Upper Bukit Timah, 11-year-old twin brothers Ethan Yap E Chern (Chinese: 叶育成; pinyin: Yè Yùchéng) and Aston Yap Kai Shern (Chinese: 叶凯胜; pinyin: Yè Kǎishèng), who were both diagnosed with autism, were murdered by the…

Why does Greenridge Crescent twin killings matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Greenridge Crescent twin killings?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Greenridge Crescent twin killings.

Tags

  • 2022 in Singapore
  • 2022 murders in Singapore
  • Child filicides
  • Child murder in Singapore
  • Deaths by strangulation in Singapore
  • Incidents of violence against boys
  • January 2022 in Singapore
  • Singaporean people convicted of manslaughter
  • Violence against neurodivergent people

Keep exploring