1) functional, dangerous, careful, beautiful, personal, helpful, famous, powerful, harmful, organic.

2)

1. can

2. could

3. must

4. must

5. have to

6. should/has to/had to, даже must можно (контекста нет, поэтому сложно сказать)

3)

1. was invented

2. is elected

3. were built

4. was discovered

5. was released

6. are visited

4)

The telegraph was invented by André-Marie Ampère and David Alter in 1874. It could record messages.

Its advantages were reliable communications and jobs creation. Its disadvantages were slow transmission speed and lack of personal touch.