1. This is known as being "double-booked". You would say something like, "I am double-booked for tonight, so I must postpone our dinner plans."
2. It is a little confusing because it is not naturally stated. It would be clearer if it said "John has already dated Mary, when they went to see the movie." Or, "John has taken Mary on a date to see the movie."
In my language, 'date' have taken a different kind of meaning. That is why I'm a little confused. It means to ask someone to go out together without any romantic meaning.
For example:
A friend: Tina, do you want to go see Iron man together?
Tina: I can't. I have already dated my sister. (I've made plans to see Iron Man with my sister)
In my language, 'date' have taken a different kind of meaning. That is why I'm a little confused. It means to ask someone to go out together without any romantic meaning.
For example:
A friend: Tina, do you want to go see Iron man together?
Tina: I can't. I have already dated my sister. Very odd thing to say in English!