单项选择题

         A
Quiet student offered
room in private house.
Share bath and kitchen.
gas/electricity

           B
Professional couple,3 children,
2,4and 6,offer single room,
rent-free, to student willing to
baby-sit 3 evenings weekly,
occasional weekends. Live as family.

        C
Double room suitable 2 students sharing.
Cooking facilities, share bathroom.
Non-smokers only.
$70each weekly, excluding gas/electricity.
           D
Teacher going on 3-month study course
abroad willing to let comfortably furnished
flat in prestige block to responsible
students. 2 double bedrooms, 1 single. Use
of garden.
Rent $70 each, weekly, inclusive.
No late parties.
For two students ad D would be more economical than ad C because ______.

A.they would share a room
B.the basic expenses are cheaper
C.there are no extras except for food
D.there is free use of the garden