The most important idea in a text is the central idea. key detail. main relationship. signal word.

central idea.

Explanation:

The central idea of a text is the main idea that the author elaborates throughout the entirety of his or her piece by means of events, story-line, dialogues, characters development, style, and idiosyncrasy. As such, the central idea can usually be summarized in a few words, and sometimes even in one or two words. An example of a central idea could be society´s hypocrisy.

what is the question that you are asking

active voice: my father cut the tree.

passive voice: the tree was cut by my father.

active voice: people buy newspapers every day.

passive voice: newspapers are bought (by people) every day.

active voice: people have been using movies as political propaganda since world war ii.

passive voice: movies have been used as political propaganda since world war ii.

active voice: donna gave me my birthday present.

passive voice: i was given my birthday present (by donna). / my birthday present was given to me (by donna).

active voice: mom will leave the keys on the counter.

passive voice: the keys will be left (by mom) on the counter.

the words in parentheses are the agent of the passive voice and can be omitted when obvious, generic, or simply unnecessary.