1 is wrong. If you want it in present, use this one: "I know it from the text/dialogue/discussing." or for past: "I've known it from the text/dialogue/discussing." 2 is good. 3 is good, too. 4 is wrong, it would be: "I'm late for the bus (at the moment).", but I'm not 100% sure.

1. If you're answering the question, "How did you know?" you'd just answer with a sentence fragment: "From the text/ dialogue/ discussion." If you really wanted to answer with a complete sentence, you'd be better off saying, "I read it in the text." "I heard it in the dialogue." "It came up during the discussion." (et cetera). 4. "I am going to miss the bus."

1. I've know it from the text/dialogue/discussing. Wrong Various suggestions depending on context. I know it from the text/dialogue/discussion. Grammatically correct but not really what we would say. I know it from reading the text. I know it from listening to the dialogue. I know it from listening to the discussion. 2. What is in the picture? Correct 3. There are only a few words in the page. Wrong - on the page 4. I late on the bus. (at the moment) - Wrong - I am late for the bus./ I am running late for the bus.