Please choose the correct ending to complete the given sentence: Youth: [header] How to be grown up [title] Act more rationally. [step] In your youth, it's more excusable for you to behave recklessly or out of self interest. However, as you enter adulthood, a big part of your responsibility will involve thinking and acting rationally.

Ending1: A new woman graduates elementary school, teenagers start dating boys, and then fall in love again. In your twenties, maturity is no longer a concern. Ending2: The key is to recognize things you don't quite understand, and avoid explaining them. [substeps] If you don't know what, remember that your parents are thinking and will bring you some knowledge later about their decision. Ending3: It's incredibly important to you start acting rationally. [substeps] First, think about why you felt the need to behave the way you did in the early phases of childhood. Ending4: [substeps] Rational thought requires you to distinguish between thinking and feeling. A rational person exercises control over his or her emotions, and acts based on thoughts instead of feelings.

Answer format: ending1/ending2/ending3/ending4