用所给动词的适当形式填空。
In many countries, 1 (smoke) is becoming a bigger problem for young people. Most smokers
2 (start) in their teens (years of a person's age from 13 to 19 ) or even earlier.
A study of 8,000 Beijing students last May 3 (show) us that smoking was a problem for many
Chinese kids. More than 21% of middle school students and 6% of primary school pupils (小学生) said
they had smoked. "If young people start 4 (smoke) early, they will probably get addicted to nicotine
(对尼古丁瘾).And it 5 (be) very hard to give up弃) later on," said a professor.
Every year, about 4 million (百万) people die (死亡) of smoking. And if people keep 6 (smoke),
that number will go up to about 10 million a year by 2030, the World Health Organization (WHO, 世界卫
生组织) says. So we have to 7 (know) and tell others about the dangers (危险) of smoking. Everyone
of us should 8 (do) something useful to stop kids from 9 (smoke), or one day we 10 (see) what
we won't see.