Answer:
7. Because we talk about a date and dates we use ''es'' if it is in the present tense.
8. Because it talks about ''Ellos'' (they) in the sentence, then in the pronoun ''Ellos'' always goes ''estan''.
9. Because it talks about clothes and in that case ''es'' is used.
10. Because here it is saying, where was the match? at the stadium, so it is indicating that it is at the stadium.
Sorry if my answers may not be of much use to you, but try to explain why.
