Ответ:

a) Base adjectives are normal adjectives that do not have the idea of 'very' (обычные). Example: beautiful (красивый), big (большой), good (хороший).

b) Strong adjectives are extreme adjectives that have the idea of 'very'. They are used instead of using "very + a normal adjective". Strong adjectives are more expressive than base adjectives (выражение очень сильных эмоций, описание какого-то ярко выраженного качества). Example: gorgeous (т.е. "very beautiful" - великолепный), huge (т.е. "very big" - огромный), great (т.е. "very good" - отличный).

c) With base: very, really, rather, quite.

With strong: absolutely, really