13.With the car________down halfway on the road, we had great difficulty walking home in the snow.
Health experts in many countries still _________ their ideas about the relationships between our food and our health.
—Can I help you,sir? —Yes,I bought this radio here yesterday,but it_________.
The last time I _________ her,she _________at a medical college.
—My watch is out of order. —Then why don’t you have _________?
I bought the telephone here yesterday but it _________ work.