He played his wife false by inviting his mistress to the house as his cousin.

Step 1: Analyze the question The question asks what the sentence really means. The key expression is "played his wife false."

Step 2: Explain the concept "Play someone false" is an idiom meaning to deceive or betray someone, especially to be unfaithful or dishonest toward them. It is not about physical actions like "playing" a game.

Step 3: Break down the sentence

• "He played his wife false" means he deceived or betrayed his wife.
• "by inviting his mistress to the house as his cousin" explains how he did it. He lied, presenting his mistress as a relative, so his wife would not suspect the affair.

So the sentence tells us that he was unfaithful to his wife and deceived her by hiding his mistress behind a false identity.

Step 4: Check each option

• A. Nothing in the sentence mentions a room. Wrong.
• B. The "cousin" is not a real cousin, and friendship is never mentioned. Wrong.
• C. He cheated on his wife with his mistress. This matches "played false" (betrayed and deceived) and the mistress involvement. Correct.
• D. "Helped his wife" has no basis in the idiom. Wrong.

Step 5: Answer

Exam tip: For idiom questions, find the idiom first and learn its meaning as a whole phrase. "Play false" = deceive or betray. Also remember related ones: "play fair" (act honestly) and "play second fiddle" (take a lesser role).