**Rule: Understanding Idiomatic Expressions.** The idiom 'the green-eyed monster' is a metaphor for jealousy. The phrase was coined by Shakespeare in his play Othello. Someone getting a promotion is a common trigger for envy in others. Option (b) is the correct definition. Option (a) is the opposite. Option (c) is a literal interpretation. Option (d) is a different emotion.

**Rule: Understanding Idiomatic Expressions.** The idiom 'full of holes' is used to describe an argument, plan, or story that is weak and has many faults, making it easy to criticize or disprove. The fact that the 'jury didn't believe it' shows its lack of credibility. Option (a) is the correct definition. Option (b) and (d) are literal misinterpretations. Option (c) is the opposite.

**Rule: Understanding Idiomatic Expressions.** The informal idiom 'a big cheese' refers to an important or powerful person in a group or organization. The sentence implies that he has an inflated sense of his own importance. Option (b) is the correct definition. Option (a) and (d) are literal misinterpretations. Option (c) is the opposite.

**Rule: Understanding Idiomatic Expressions.** The idiom 'the spitting image of' (or 'spit and image') means to have an exact likeness or resemblance to someone else, particularly a relative. Option (b) is the correct definition. Option (a) is a literal misinterpretation. Option (c) is the opposite. Option (d) is a type of image, but not the meaning of the idiom.

**Rule: Understanding Idiomatic Expressions.** The idiom 'open a can of worms' means to take an action that inadvertently leads to a host of new, unforeseen troubles. The fact that the policy 'creating more problems than it solved' is a clear example of this. Option (b) is the correct definition. Option (a) is a literal interpretation. Option (c) and (d) are the opposite of the idiom's meaning.

**Rule: Understanding Idiomatic Expressions.** The term 'vested interest' refers to a strong personal reason for wanting something to happen because one will benefit from it. Owning stock in a company gives a person a direct financial reason to want the company to succeed. Option (a) is the correct definition. Option (b) is a literal misinterpretation of 'vest'. Option (c) is the opposite of a personal interest. Option (d) is the opposite of having a strong interest.

**Rule: Understanding Idiomatic Expressions.** The idiom 'the talk of the town' refers to a person or subject that is the main topic of gossip and discussion among many people in a community. A 'heroic rescue' is a newsworthy event that would generate such widespread discussion. Option (b) is the correct definition. Option (a) and (c) are the opposite. Option (d) is a different kind of 'talk'.

**Rule: Understanding Idiomatic Expressions.** The idiom 'tied up' means to be busy and unavailable. Being 'in a meeting' is a common reason for being tied up. Option (b) is the correct definition. Option (a) is a literal misinterpretation. Option (c) is the opposite. Option (d) is an unrelated detail.

**Rule: Understanding Idiomatic Expressions.** The idiom 'sworn enemies' refers to two or more people who are irreconcilably hostile towards one another. The phrase implies a deep and enduring animosity. Disagreeing on 'every issue' is characteristic of such a relationship. Option (b) is the correct definition. Option (a) is a literal interpretation of 'sworn'. Option (c) is the opposite. Option (d) is a possible but separate fact.

**Rule: Understanding Idiomatic Expressions.** The idiom 'worth one's salt' means to be competent and effective in one's job. The phrase originates from ancient Rome where soldiers were sometimes paid in salt (salarium, the origin of 'salary'). The negative form ('not worth his salt') means someone is incompetent. Option (a) is the correct definition. Option (c) is the opposite. Options (b) and (d) are literal misinterpretations.