**Rule: Understanding Idiomatic Expressions.** The idiom 'a loose cannon' refers to a person who is unpredictable and uncontrollable and who may cause problems for their own side. The phrase 'you never know what he's going to say or do' is a direct explanation of their unpredictability. Option (b) is the correct definition. Option (a) is the literal origin of the idiom (on old warships). Option (c) is the opposite. Option (d) is a literal interpretation.

**Rule: Understanding Idiomatic Expressions.** The idiom 'leave in the lurch' means to abandon someone when they are in a difficult situation. A 'sudden resignation' of a key leader can leave an organization in a state of confusion and difficulty. Option (a) is the correct definition. Options (b) and (c) are the opposite of the situation described. Option (d) is unrelated.

**Rule: Understanding Idiomatic Expressions.** The proverb 'don't count your chickens before they hatch' is advice to not be too confident in a future outcome and not to make plans based on it until it is certain. The fact that the job offer isn't 'official yet' means the outcome is not certain. Option (a) is the correct explanation. Option (b) is a literal interpretation. Option (c) is the opposite of the caution advised by the proverb. Option (d) is illogical.

**Rule: Understanding Idiomatic Expressions.** The idiom 'run riot' means to behave in a noisy, violent, and uncontrolled manner. This is a common way to describe children who are left unsupervised. Option (c) is the correct definition. Option (a) and (d) are the opposite of this behavior. Option (b) implies an organized protest, whereas 'run riot' implies chaos.

**Rule: Understanding Idiomatic Expressions.** The idiom 'bear fruit' means to yield positive or successful results. Becoming a 'successful author' is the positive result of her 'years of hard work.' Option (a) is the correct definition. Option (b) and (d) are literal misinterpretations. Option (c) is the opposite of the idiom's meaning.

**Rule: Understanding Idiomatic Expressions.** The idiom 'it's all Greek to me' is used to say that one does not understand something at all, as if it were in a foreign language one does not speak. A 'complex theory' can often be incomprehensible to a non-expert. Option (c) is the correct definition. Option (a) is a literal interpretation. Option (b) is the opposite. Option (d) might be true, but it is not the meaning of the idiom.

**Rule: Understanding Idiomatic Expressions.** The idiom 'on its last legs' refers to something that is in a very weak state and near to collapse, failure, or death. The expectation of bankruptcy clearly indicates that the company is failing. Option (a) is the correct definition. Option (b) and (c) are incorrect interpretations of 'legs.' Option (d) is the opposite of the idiom's meaning.

**Rule: Understanding Idiomatic Expressions.** The idiom 'by the skin of one's teeth' means to only just manage to do something; to succeed by the smallest possible margin. Since teeth do not have skin, the 'margin' is essentially zero, emphasizing how close to failure one was. Option (d) is the correct definition. Option (a) is the opposite. Option (b) is a possible reason for passing, but not the meaning of the idiom. Option (c) is a nonsensical literal interpretation.

**Rule: Understanding Idiomatic Expressions.** The idiom 'cut no ice' (usually used in the negative) means to fail to have any influence or impact. If the lawyer's argument had no effect on the jury, it means they were not persuaded by it. Option (a) is the correct definition. Option (b) and (c) are literal misinterpretations. Option (d) is the opposite.

**Rule: Understanding Idiomatic Expressions.** The idiom 'a taste of one's own medicine' means to receive the same kind of negative treatment that one has given to others. It is essentially retaliation in kind. Betrayal is an unpleasant act, and the idiom implies an equally unpleasant response. Option (a) is the correct definition. Option (b) and (d) are literal misinterpretations. Option (c) is the opposite of retaliation.