A. talk/ read/ know about ~; tell somebody about ~; have a discussion about something, but discuss something (no preposition); do something about something = do something to improve a bad situation
A1. care about (= care for and take care of): care about somebody/ something = think that somebody/ something is important. We say ‘care what/ where/ how ~’ etc. (without about); care for somebody/ something (1) = like something (usually in questions and negative sentences) (2) = look after somebody
A2. dream about ~ (when you are asleep), dream of/ about being something/ doing something = imagine; wouldn’t dream of doing something = I would never do it
A3. hear about ~ = be told about something; hear of ~ = know that somebody/ something exists; hear from ~ = receive a letter, phone call or message from somebody
A4. think about ~ and think of ~, When you think about something, you consider it and concentrate your mind on it. When you think of something, the idea comes to your mind, also use think of when we ask or give an opinion; Also, can say think of or think about doing something (for possible future actions)
A5. remind somebody about ~ = tell somebody not to forget; remind somebody of ~ = cause somebody to remember
A6. complain (to somebody) about ~ = say that you are not satisfied; complain of a pain, an illness etc. = say that you have a pain etc.
A7. warn somebody about a person or thing which is bad, dangerous, unusual etc.; warn somebody about/ of a danger, something bad which might happen later.