What do you think about this introduction to answering Yes/No questions? I have found a lot of information about asking questions but very little about answering them.

I want to create a rule to help learners answer affirmative/negative questions in Chinese. Presently I ask them to identify the following in a sentence: copulas, modals, main verbs or solitary adjectives and then use them in one or two-word answers. My question is how would you answer the following questions in the simplest way:


李先生在吗？
他是你的朋友吗？
李先生很累吗？
你要这张卡片吗？
李先生有朋友吗？
First answer is yes, and next answer is no:


李先生在吗？
在/不在
他是你的朋友吗？
是/不是
李先生很累吗？
累(This is shortest, but in real life people wouldn't answer like that)/不累(This is native.)
你要这张卡片吗？
要/不要
李先生有朋友吗？
有/没有


And using the 嗯 to make no answer is not the right way, people don't speak like that.