The key answer of exercise 1

b)

1. children can be difficult, long hours, do extra work
2. working with children is important and (like teaching) it affects the future
3. firefighter
4. dangerous
5. research biologist
6. the whole world benefits

c)

question 1

1. Speaker 3, the research biologist. He wants more money for the lab.
2. Speaker 2, the firefighter. Firefighters save some (stupid) people who 'fell asleep with a cigarette in their mouth or forgot to switch off the oven.
3. Speaker 1, the nanny. Cleaning and cooking.