A、18. B、54. C、65. D、12 000. D短文开始部分提到，来自瑞典隆德大学的一项研究表明，乘汽车、公交车或列车上下班的人更容易感到压力大和精疲力竭。负责该研究的科学家评估了1．2万名年龄在18岁到65岁之间的员工的状况。

Workers who commute by car, bus or train to the office are more likely to suffer from stress and exhaustion, according to a sudy from Lund University in Sweden.(18)Scientists assessed 12 000 employees aged between 18 and 65. They found that those who travelled to work by car or public transport reported higher levels of stress and tiredness compared to active commuters who travelled by foot or bicycle.(19)It is now expected that the study will encourage further investigation into the health impacts of commuting and the best forms of transportation Researcher Erik Hansson said car and public transport users suffered more everyday stress, poorer sleep quality, and exhaustion. He also says the negative health of public transport users increases with journey time According to the Office for National Statistics, the average Briton commutes for 54 minutes every day.(20)But now the scientists claim that the advantages of daily commuting, such as higher pay or housing conditions, need to be weighed against the adverse health effects. Income, family background and environmental factors are other variables that need to be considered. Hansson added that the study would help to readdress the balance between economic needs, health, and the costs of working days lost.
18. How many employees does the study in this passage survey?
19. What can we learn about the study?
20. What’s an advantage of daily commuting according to the passage?