The sentence "You weren't supposed to do that" expresses a past expectation or rule that was broken. It means that an action was performed, but it was against what was intended, planned, or allowed.

Let's analyze the structure and meaning:

• "Weren't supposed to" is a phrase used to indicate a past prohibition or that something was not the correct or expected thing to do.
• The use of the past tense "weren't" and the infinitive "to do" implies that the action ("do that") has already been completed by the person being addressed.
• Therefore, the core meaning is about a past action that should not have occurred.

Now, let's evaluate the options:

Option 1: "You shouldn't do that, but you do."
This refers to a present or general prohibition and a current habit. It does not match because our original sentence is about a single past action, not a recurring present action.

Option 2: "You shouldn't have done it."
This is a direct and perfect match. "Shouldn't have + past participle" is the grammatical structure used to criticize or express disapproval about a past action. It carries the exact same meaning as "weren't supposed to do that."

Option 3: "You should have done it, but you didn't."
This expresses regret about a past action that was not performed. It is the opposite of the original sentence's meaning.

Option 4: "You should do that, but you don't."
This refers to a present or general obligation that is being ignored. It does not match the past context of the original sentence.

Final Answer

The option closest in meaning is: "You shouldn't have done it."

Related Topic: Modals of Obligation and Advice (Past Forms)

This question tests your understanding of modal verbs like 'should' and quasi-modal expressions like 'be supposed to' when used to talk about the past.

• Should have + past participle: Used to give advice about the past or to express regret that something was not done.
  Example: "I should have studied more." (I didn't study enough, and I regret it now.)
• Shouldn't have + past participle: The negative form, used to say that a past action was a mistake.
  Example: "You shouldn't have said that." (You said it, and it was the wrong thing to do.)
• Was/Were supposed to + infinitive: Used to talk about an expectation, rule, or plan in the past. The negative form ("wasn't/weren't supposed to") means an action was not expected or was against the rules.
  Example: "He wasn't supposed to leave." (He was not allowed to leave, but he did.)

The phrases "shouldn't have done" and "weren't supposed to do" are very close synonyms in this context.