Hi Hamed If someone answers a question clearly, you wouldn't really use any of those words. You would say "You answer was clear" or "I understand that now" or something similar. As for the words you ask about, I'd say the following: "Comprehensible". This is rarely used. However "Incomprehensible" is commonly used. If, for example an essay was so unclear and garbled that it was impossible to understand, you'd say it was incomprehensible. "Comprehensive". This means "complete". So, if an answer was very thorough and included all relevant information, you'd say it was a comprehensive answer. "Understandable". You would not normally say, "That text/answer/essay was understandable". This word usually refers to a situation or a state. For example, you might say "Mr A hasn't had any training, so his mistake was understandable". Or, if someone said to you, "Mrs J just lost her job, so she doesn't feel like talking much" you might reply "Oh, that's understandable". Finally "Realise". This normally has two senses. First, if you realise something, it means something has become clear to you, usually as a result of an experience and over a period of time e.g. "When the day became dark with clouds, I realised it was going to rain". "Realise" also has a different sense, which is "to make something concrete" e.g. "His ideals were finally realized". It's in the sense that you may use the form "realisable" e.g. "Is this project realisable. These are all difficult words, but I hope you found my explanations useful Alan Baker

The words "understandable" and "comprehensible" mean the same thing. However, "comprehensible" sounds much more formal, and is not very common. On the other hand, "comprehensive" has a totally different meaning. Comprehensive means complete, thorough, and not lacking in any way. So, if you say that an answer is comprehensive, it means that it was a very thorough answer. I hope this is helpful!

'Understandable' and 'comprehensible' are synonyms. They mean that you are able to understand something i.e. you understand the words that have been used and the message they are trying to convey. They don't fit if you want to reply to someone who has given you a very good answer. As an example, if someone writes something using broken English, but I can still understand what they are trying to say, then their answer is understandable/comprehensible. Or if I am speaking to someone and I cannot understand what they are saying very well, you could say they are barely comprehensible/understandable. 'Comprehensive' is the word you would use if you want to reply to someone who has given you a very detailed answer. A comprehensive answer is one which is detailed, and contains all the main points you could hope to receive. A 'comprehensive answer' doesn't necessarily have to be easy to understand, it's about the amount of information given in the answer. In actual fact I think what you want to say is that someone's answer is 'easy to understand' or is 'very clear.' That means they use simple, clear language that you find very helpful and easy to understand. There is a clear difference between saying that and saying something is 'understandable/comprehensible.'

@Paul: Hi. Thank you very much. I've got it. I appreciate it.