I.Điền một từ thích hợp vào chỗ trống
Many people nowadaya have to wear false teeth when they was middle-aged. Since the beginning of this century,(1)................. decay has greatly increased. The amount(2)..............sugar in our food has aslo increased Doctors and dentists now know that(3)............... in the chief cause of tooth(4)................Eskimos'teeth, for example, started to(5)...........when thay began to eat sweet(6)..................
Long age doctors did not like(7)..........treat people's teeth. Barbers and blacksmiths(8)...........after people's teeth and pulled them(9).............when thay decayed. Some people thought(10).................. was a punishment from the gods.