1) This part of the country is rich oil.
CORRECT! RICH + IN
2) A mile is a unit of distance equal 5,280 feet or exactly 1.609344 kilometres.
CORRECT! EQUAL + TO
3) Gina was absent school with a cold.
CORRECT! ABSENT + FROM
4) She continued on her way, ignorant the dangers that lay ahead.
CORRECT! IGNORANT + OF | ABOUT
5) It was obvious me that they had been here before.
CORRECT! OBVIOUS + TO
6) My cousin was delighted his new car.
CORRECT! DELIGHTED + WITH
7) Ted was fortunate having a good teacher.
CORRECT! FORTUNATE + IN
8) I'm related her - she's my sister.
CORRECT! RELATED + TO
9) We are so thankful all the support and solidarity.
CORRECT! THANKFUL + FOR
10) Why is she being so mean me? I didn't do anything.
CORRECT! MEAN + TO