**Rule: Understanding Idiomatic Expressions.** The idiom 'sell like hot cakes' means to be sold very quickly and successfully. The fact that the tickets 'sold out in minutes' is a clear example of this. Option (b) is the correct definition. Option (a) is a literal interpretation. Option (c) is incorrect. Option (d) is the opposite of the idiom's meaning.

**Rule: Understanding Idiomatic Expressions.** The idiom 'go their separate ways' means to dissolve a relationship, partnership, or association. In the context of countries with 'political disputes', it signifies the end of their cooperation. Option (a) is the correct definition. Option (b) is a literal meaning but not the figurative one intended. Option (c) is the opposite. Option (d) is unrelated.

**Rule: Understanding Idiomatic Expressions.** The idiom 'keep a straight face' means to avoid laughing or showing amusement, even though one finds something funny. The fact that he 'burst out laughing' shows that he failed in his attempt to keep a straight face. Option (c) is the correct definition. Option (a) is a literal interpretation. Option (b) and (d) describe different expressions.

**Rule: Understanding Idiomatic Expressions.** The idiom 'to have a bee in one's bonnet' means to be obsessed with an idea or to be constantly thinking and talking about something, often to the point of annoyance for others. It implies a strong and persistent preoccupation. Option (b) is the correct definition. Option (a) is a literal and uncomfortable misinterpretation. Option (c) is the opposite. Option (d) is unrelated.

**Rule: Understanding Idiomatic Expressions.** The idiom 'take the bull by the horns' means to face a challenge or difficulty directly and decisively. Confronting one's boss is a difficult situation that requires courage. Option (b) correctly defines this approach. Option (a) and (d) are literal misinterpretations. Option (c) is the opposite of the idiom's meaning.

**Rule: Understanding Idiomatic Expressions.** The idiom 'just what the doctor ordered' refers to something that is precisely what is needed or desired to improve a situation. An 'inspiring speech' is exactly what a team with 'low morale' needs. Option (b) is the correct definition. Option (a) is the literal origin of the phrase. Option (c) is the opposite. Option (d) is a literal misinterpretation.

**Rule: Understanding Idiomatic Expressions.** The idiom 'straight from the horse's mouth' means that the information comes from the most direct, authoritative, or reliable source. This phrase is used to emphasize the authenticity of the information. Option (c) is the correct definition. Option (b) is the opposite (e.g., 'through the grapevine'). Options (a) and (d) are incorrect, literal interpretations.

**Rule: Understanding Idiomatic Expressions.** The idiom 'eat one's words' means to retract a statement or admit that what one said was incorrect, often in a humiliating way. If someone boasts and their team loses, they are forced to admit their prediction was wrong. Option (b) is the correct definition. Option (a) is a literal misinterpretation. Option (c) is unrelated. Option (d) would only happen if his boast was correct.

**Rule: Understanding Idiomatic Expressions.** The idiom 'a long shot' refers to an undertaking, guess, or attempt that has a very low probability of success. The phrase 'but the teacher believed him' implies that the success of the explanation was surprising and unlikely. Option (a) is the correct definition. Option (b) describes length, not probability. Option (c) is a literal meaning from photography. Option (d) is the opposite of a long shot.

**Rule: Understanding Idiomatic Expressions.** The idiom 'up in arms' means to be very angry and protesting strongly about something. A plan to build a highway through a neighborhood is a common cause for community outrage. Option (c) correctly defines this reaction. Option (a) and (d) are literal misinterpretations. Option (b) is the opposite of the community's angry reaction.