Which is correct?

They want my sister and I to go away.

They want my sister and me to go away.

I think it's the first one?

Take the other person out of the question .

would you say "They want I to go away" or would you say "They want me to go away" ?

Does that answer your question and give you some help ?

Ahh -- you Australians have the same trick we do. :-)

The correct sentence is: "They want my sister and me to go away."

To determine whether to use "I" or "me" in a sentence, you can try removing the other person and see which pronoun sounds better. In this case, if we remove "my sister," the sentence would be: "They want I to go away." This doesn't sound right, so we can conclude that "me" is the correct pronoun to use.

Another way to understand this is by identifying the object of the verb. In this sentence, the object of the verb "want" is "my sister and me." Since "me" is used when it is the object of the verb, "my sister and me" is the correct form.

Therefore, the correct sentence is: "They want my sister and me to go away."