This will save you a great deal of embarrassment and unnecessary effort. Don't ask somebody out if they are in a relationship. Not only is it essentially guaranteed that they'll say no, but it is inappropriate, unfair to the person's boyfriend/girlfriend, and reflects poorly on your moral character. Decide beforehand what you will do or say if the person says no. This is especially important if you plan on asking out a friend, as it will reduce the likelihood of damaging the friendship.  Being prepared for rejection will help you avoid appearing physically defeated in front of the other person if the answer is no.  While you want to prepare yourself for the possibility of rejection, don't let it get in the way of your confidence. Rather, let it build on your confidence by accepting the fact that being rejected isn't the end of the world. This will help you think of a good idea for a date. If this person loves music, find out what kind and invite them to a concert. If they enjoy movies, then invite them to the theater, and so on. If you are too shy to do the asking in person, then consider sending a text, Facebook message, or email.  Text messages are a good option if you are too afraid to do the asking in person. This way, you will at least be able to hide your disappointment from the other person. If you  have just met the person and don't have their number, you will have to do the asking in person, but don't fret! Doing the asking in person is romantic and can be very rewarding if the person says yes.

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Write a summary of the previous text in Chinese:
看看这个人是不是已经有对象。 自信，但要做好被拒绝的准备。 可能的话，找出他/她喜欢的东西。 决定如何约会这个人。