1. I've spent all my money already.

2. She spent ¡Ì100 on a new dress.
3. I've used all my money already.
4. She used ¡Ì100 on a new dress.
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Can we use both 'spent' and 'used' in the sentences?

5. I used up my allowance in two days.
6. I didn't want to break up with her.
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Does 'up' mean 'completely' in each sentence?

In 3 and 4, I'd include "up" -- to use up something means it's all gone. In this case, you're referring to money. But 1, 2, 3, and 4 are not completely interchangeable.

In 5, yes, the word "up" means completely.

In 6, "up" is just part of that phrasal verb that means they ended their relationship.

1. Yes, both "spent" and "used" can be used in these sentences. They both convey the idea of using money to purchase or pay for something.

2. You can find the answer to this question by looking at the verb tense and the context of the sentence. In this case, it suggests that the action of spending £100 on a new dress is already completed. The past tense implies that it has happened in the past and is not ongoing.

3. Similar to the previous sentences, both "spent" and "used" can be used here. They both indicate that all of the money has been used or consumed.

4. Again, the verb tense and context of the sentence indicate that the action of using £100 on a new dress occurred in the past and is completed.

5. Yes, in this sentence, "used up" means "completely." The addition of "up" intensifies the action, indicating that the entire allowance was used or consumed within two days.

6. No, in this sentence, "break up" means the end of a romantic relationship. It does not mean "completely" in this context. "Break up" is a phrasal verb that refers to the termination of a romantic connection between two people.