Most of these are neither right nor wrong, but are statements vs. questions. So that, "They are not my friends" and "Are they not my friends?" Are both correct, but one is a statement while the other is a question (though a touch archaic in its formulation. "Aren't they my friends?" would be more modern.) However, there are a few mistakes. "Is your new plan great?" Is a perfectly acceptable question. "Your new is great plan?" Doesn't quite work. It's trying to use new, which is an adjective, as a noun. Many words that are usually adjectives can be used as nouns (for instance, "That red is very bright."), but in this context, new can only be an adjective. Fortunately, if we just move "plan", a noun, so that it new is referring to it, we get, "Your new plan is great." which is a perfectly acceptable sentence. Note that "Your new plan is great." is a statement, while, "Is your new plan great?" is a question. These follow the basic rule for creating simple statements and simple yes/no questions in English. /When are you usually home? Is a perfectly acceptable question. /I am not good at English? Is a statement. We therefore end it with a period rather than a question mark. "I am not good at English." /Am I not good at English? Is a perfectly acceptable sentence, though it is a touch archaic. A more modern phrasing would probably either drop the negative, "Am I good at English?" or use a contraction, "Aren't I good at English?" There's a slight difference in connotation between these. "Am I good at English?" is just asking, while with "Aren't I good at English?" presumably believes they are pretty good at English. /Who says? Is a perfectly acceptable question. /Where do you go? Is, again, a perfectly acceptable question. I hope this is helpful. Cheers.