**Rule: Understanding Idiomatic Expressions.** The idiom 'feel it in one's water' is a British expression meaning to have a premonition or a gut feeling about something, without having any concrete evidence. It is similar to 'feel it in one's bones'. Option (a) is the correct definition. Option (b) and (d) are literal misinterpretations. Option (c) is the opposite of having a strong feeling.

**Rule: Understanding Idiomatic Expressions.** The idiom 'pour oil on troubled waters' means to say or do something to pacify a quarrel or calm a tense situation. It originates from the ancient practice of pouring oil on the sea to calm the waves. A 'heated debate' is a situation that needs calming. Option (b) is the correct definition. Option (a) describes 'adding fuel to the fire'. Option (c) is a literal interpretation. Option (d) is a different approach.

**Rule: Understanding Idiomatic Expressions.** A 'fair-weather friend' is someone who is only friendly and supportive when it is easy or convenient for them. The phrase 'never around when I have problems' is a direct explanation of this type of unreliable friend. Option (a) is the correct definition. Option (c) is the opposite. Options (b) and (d) are literal misinterpretations.

**Rule: Understanding Idiomatic Expressions.** The idiom 'a castle in the air' (or 'castles in the sky') refers to an extravagant plan or hope that is impractical and has no solid foundation. The lack of 'realistic funding or timeline' confirms the impracticality of the project. Option (b) is the correct definition. Option (a) is the opposite. Option (c) and (d) are literal misinterpretations.

**Rule: Understanding Idiomatic Expressions.** The word 'cheek' is used idiomatically to mean audacity, impudence, or behaviour that is bold in a rude way. Asking for more money without repaying a previous debt is a classic example of cheeky behaviour. Option (c) is the correct definition. Option (a) is the literal meaning. Options (b) and (d) are the opposite of having cheek.

**Rule: Understanding Idiomatic Expressions.** The idiom 'in the black' means to be financially profitable. It comes from the accounting practice of using black ink to indicate profits, as opposed to red ink for losses. Option (b) is the correct definition. Option (a) describes being 'in the red'. Option (c) is an incorrect interpretation. Option (d) is a literal misinterpretation.

**Rule: Understanding Idiomatic Expressions.** The idiom 'between the devil and the deep blue sea' describes a dilemma where one must choose between two equally difficult or dangerous alternatives. Being forced to choose between two 'bad job offers' is a perfect example. Option (a) is the correct definition. Option (b) and (d) are literal misinterpretations. Option (c) is the opposite.

**Rule: Understanding Idiomatic Expressions.** The idiom 'hit the nail on the head' means to be exactly right about something. It signifies a precise and accurate observation or statement. Option (a) is the correct definition. Option (b) is the literal action. Option (c) is the opposite. Option (d) is an unrelated action.

**Rule: Understanding Idiomatic Expressions.** The idiom 'up in the air' is used to describe something that is not yet settled or decided. It implies a state of uncertainty. Option (b) is the correct definition. Option (a) is the opposite. Option (c) and (d) are literal misinterpretations.

**Rule: Understanding Idiomatic Expressions.** The idiom 'curry favour' means to ingratiate oneself with someone through insincere praise or actions in order to gain an advantage. Promising tax cuts is a common political tactic to win votes. Option (b) is the correct definition. Option (a) is a literal misinterpretation. Option (c) implies sincerity, which the idiom does not. Option (d) is the opposite.