instruction:
Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.
question:
Possible Duplicate: Which is the proper spelling: 'disfunction' or 'dysfunction'? What's the rationale behind dysfunctional being spelled dys- and not dis-?.
answer:
From WordReference.com on Dysfunction vs. Disfunction: dys- is a Greek prefix meaning 'bad', 'abnormal', 'difficult', or 'impaired'. dis- is a Latin prefix with none of the above meanings. dys- has the right meaning, but function is a Latin word. Hence the confusion. Latin dis- can mean 'lack of', 'not', 'opposite of', 'away from'. This all explains why something dys-functional has a bad or abnormal function, rather than a lack of function that dis-functional implies.


question:
The word year when pronounced starts with a phonetic sound of e which is a vowel sound making it eligible for being preceded by an. Yet, we tend to write a year. Why?.
answer:
I reject your premise that the word year starts with a phonetic sound of e. Here's how it is pronounced according to the various dictionaries: Wiktionary: (RP) IPA: /ji/, /j/, SAMPA: /ji@/, /j3:/; (US) enPR: yir, IPA: /ji/, SAMPA: /jir/ Merriam-Webster: \yirAmerican Heritage Dictionary of the English Language: /yir/ Collins English Dictionary: /j/ Words that start with the /j/ sound are preceded by an a, not by an an. Compare: a user, a utility, a yak.


question:
In my language, when I write an email to my professor, boss, etc, there is a greeting part in the first part of email right after 'Dear prof. ...'(in my language of course), e.g. 'How are you', 'I hope everything is alright' and so on. But I don't have any idea how can I write a proper email with such a greeting in English? Or do I have to ignore it because the email is kinda formal?.
answer:

I almost always start formal e-mails with Dear Professor _, I hope this note finds you well. Some guidelines will suggest ending your salutation with a colon rather than a comma, but in many circumstances a comma is acceptable. If the person's title is 'professor,' you should spell it out (not 'prof.') and begin it with a capital letter when it precedes the person's name (as it would in your example). 'I hope this note (or letter) finds you well' politely establishes a friendly connection between you and the recipient of your letter and in most circumstances is a great way to start it. Especially if you're asking for something, it's good to indicate your concern for the person you're writing to. For the same reason, it's a good idea to end the letter with a phrase or sentence that will similarly show interest in their work or their well-being. 'Best regards,' is fine, but if you can tailor it in a way that's a bit more thoughtful, it's better. 'I hope your book/project continues to go smoothly.' (This can be followed by a 'Best regards.') If this is a person you don't know, you may have to settle for a generic 'Best regards' alone.