It's a date.用于比较亲密的朋友约定某件事情。属于较随便的表达，可以拉近彼此之间的距离。如果使用在比较正式的场合，就不太合适。另外，男性之间也不使用这种说法。
SCENE 1
Chris: Would you like to have Sichuan food with me? 愿意和我一起去吃川菜吗？
Rose: It sounds good. So what time? 听起来不错，几点钟？
Chris: How about 5:30? 五点半如何？
Rose: It's a date. 一言为定。
SCENE 2
Rena: When will you finish your work tonight? 今晚几点下班？
Chris: By 8 o'clock. 八点以前吧。
Rena: Then afterwards, why don't we go for a drink at the Shanghai Hotel? 这样吧，我们约好8：30在上海宾馆吃宵夜，如何？
Chris: Ok, it's a date. 好啊，就这么说定了。
SCENE 3
Donna: Are you free on Saturday morning? 周六有空吗？
Helen: Yes, I am. 是的，我有空。
Donna: How about going to the New Appearance Photo Room to take some photos? 那么我们约好一起去新形象照相馆照相，好吗？
Helen: Good idea! It's a date. 好主意，就这么办。
