Надо ответить на вопрос: can you give examples of the 20th-century inventions that in your opinion influenced the development of our civilization in a most dramatic way ?

окей . In my opinion the most important invention of the 20th century is PC(personal computer) . everyone knows that pc is very useful devise / you can find any informaton you need just serfing the internet. the second invention - alternating current is as important as the previous one. without it our world would have been absolutely different ! just imagine the world without radio , television, light , electric trains and metro ...