there's not much .. in the countryside. People usually enjoy the fresh air there

a. noise

b. water

c. pollution

d. air

some folk games in the countryside can keep children away .. their cell phones

a. to 

b. from

c.for

d. with

most students in my class are hard-working. They.. finish all their homework before they come to class

a. always

b. sometimes

c. rarely

d. never