My grandma stays----though she is 80 years old.

My grandma stays____though she is 80 years old.
A.health B.healthly (为什么是B)
I find it difficult___English well.
-_____hard,and you'll make it.
A.to learn Work B.learing;to work
C.learning;work D.to learn;to work (不是difficult in doing吗?为什么不是to work)
How did you deal___the problem?
Is was very kind____her to help me.
A.with of B.with for C.about of D.about for