Chapter 4: Traps & Discrimination

Key Vocabulary

Confusable concepts, NOT/EXCEPT questions, common distractors, harder questions. This chapter trains the "almost picked the wrong one" instinct.

中文快速導讀：本章不是背更多名詞，而是分清「兩個很像但其實不同」的概念。做題時先找 NOT（不是）、EXCEPT（除了）、incorrect（不正確）等否定字；它們表示要找錯誤選項，不要急著找正確敘述。

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1. Confusable-Concept Table（相似概念辨識表）

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2. NOT / EXCEPT Style Questions（NOT / EXCEPT 型題目練習）

中文讀題提示：Which of the following is NOT ...? = 「以下哪一項不是……？」；which statement is incorrect? = 「哪個敘述不正確？」。先在題幹圈出否定字，再逐項排除。

1. Which of the following is NOT one of the computer's five main components? 中文提示：以下哪一項不是電腦五大功能組成部分？ A. Input　B. Processing　C. Storage　D. Graphics card 　→ D. The five components are input, processing, output, storage, communication（輸入、處理、輸出、儲存、通訊）— "graphics card" is a piece of hardware, not a functional category.

2. About cloud computing, which statement is incorrect? 中文提示：關於雲端運算，哪一個敘述不正確？ A. SaaS users don't manage the OS　B. IaaS users install their own OS　C. PaaS users must manage the hardware themselves　D. All three models share resources over a network 　→ C. Under PaaS, the vendor already manages hardware and OS — the user focuses purely on application development.

3. Which of the following is NOT a typical social engineering technique? 中文提示：以下哪一項不是典型的社交工程手法？ A. Impersonating a bank's customer service caller　B. Exploiting a firewall vulnerability to breach a server directly　C. Sending a phishing email pretending to be a colleague　D. Exploiting someone's trust to obtain a password 　→ B. Social engineering's core is exploiting human weakness, not technical vulnerabilities — attacking a firewall exploit directly is a technical attack, not social engineering.

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3. Full Distractor Analysis（完整拆解練習，分析每個選項為什麼對／錯）

Question: About TCP and UDP, which statement is correct? 中文提示：關於 TCP 與 UDP，哪一項敘述正確？ A. TCP is connectionless, UDP is connection-oriented B. TCP requires a three-way handshake before transmission; UDP does not C. UDP is more reliable than TCP because UDP has error retransmission D. Both TCP and UDP are Network-layer protocols

• Correct answer: B
• Why correct: TCP must confirm both sides are ready via a three-way handshake before sending; UDP sends directly with no connection setup.
• Why the others are wrong: A has the characteristics swapped; C wrongly attributes "reliability" to UDP — TCP is the one with retransmission; D is wrong on layer — TCP/UDP are Transport-layer, not Network-layer.
• Common trap（常見陷阱）: swapping "connectionless/connection-oriented" or "reliable/unreliable" between the two protocols.
• How to recognize next time（下次怎麼認）: any statement claiming "UDP is more reliable" or "TCP needs no connection setup" is automatically wrong.

Question: About Digital Signatures, which statement is correct? 中文提示：關於數位簽章，哪一項敘述正確？ A. A digital signature's main purpose is to encrypt content so it can't be read B. A digital signature uses symmetric encryption with a shared key C. A digital signature ensures integrity, authenticity, and non-repudiation D. A digital signature is identical to an electronic signature (e.g. a scanned handwritten signature)

• Correct answer: C
• Why correct: This is the standard definition — these three terms（完整性、真實性、不可否認性）appear in past papers almost every year.
• Why the others are wrong: A confuses "signing" with "encrypting" — a signature verifies source, it doesn't hide content; B is wrong on mechanism — digital signatures use asymmetric encryption (public/private key); D conflates a technical verification mechanism with a plain image of a signature.
• Common trap: mistaking a digital signature's function for "encrypting content."
• How to recognize next time: seeing "integrity, authenticity, non-repudiation" together almost always points to this answer.

Question: About the subnet mask 255.255.255.192 (/26), which statement is correct? 中文提示：關於子網路遮罩 255.255.255.192 (/26)，哪一項敘述正確？ A. This subnet can hold up to 64 devices B. This subnet can hold up to 62 devices C. /26 means the host portion has 26 bits D. This mask holds more devices than /24

• Correct answer: B
• Why correct: /26 means 26 network bits, so host bits = 32−26=6, giving 2⁶−2=62 (after subtracting the network and broadcast addresses).
• Why the others are wrong: A forgets to subtract the two reserved addresses; C misreads /26 as host bits instead of network bits; D has the logic backwards — /26 has more network bits than /24, so it actually holds fewer hosts.
• Common trap: forgetting the "−2" in 2ⁿ−2, or misreading /n as the host-bit count.
• How to recognize next time: seeing /n, first convert host bits = 32−n, then apply the formula — don't skip the conversion step.

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4. Advanced Question Bank（高難度進階題庫，時間充裕再讀）

Source（來源）: harder technical items from NotebookLM's auto-generated flashcards and mind map — suited for students already comfortable with the basics, pushing for extra marks.

These items lacked full explanations in the original source; answers have been cross-checked against the mind map and flashcards, so they're safe to memorize.