Susan used to__to school,but she is used to ___ to school no

Susan used to__to school,but she is used to ___ to school now.
A.walk ; take a bus B.walk ; riding a bikes.
C.walk ; ride a bike D.walked; took a bus
Buses ___ passengers.
A.are used to carring B.are used to carry
C.used carry D.get used to carry
I don't suppose you're ccareless ,______?
A.don't you
B.aren't you
C.do I
D.Are you
为什么?