Yes, "year-round" should be hyphenated when used as an adjective to describe something that occurs throughout the entire year. For example, you would say "year-round activities" or "year-round service." However, when used as an adverb, it can be written as two separate words, such as "available year round."
It does not need to have a hyphen! :)
No, "semifinal" does not have a hyphen in it. It is a single, compound word that refers to a match or round that precedes the final in a competition. The correct spelling is "semifinal," without any hyphen.
When I take part in a round table, the event is two words. When used attributively, it is hyphenated, eg I attended a round-table discussion. It is a modifier, two words joined together with the hyphen.
Yes, "year-end" should have a hyphen when used as an adjective, such as in "year-end report." However, when used as a noun, it can be written as "year end" without a hyphen. The hyphen helps clarify that the two words function together as a single descriptive term.
No, the word "nineteen" does not need a hyphen when written numerically.
Yes, "year-ended" typically has a hyphen when used as a compound adjective before a noun, such as in "year-ended financial report." The hyphen helps clarify that the two words work together to modify the noun. However, when used in other contexts, such as "the report for the year ended," the hyphen is not needed.
No
I do not believe that multitasking is supposed to have a hyphen.
It's not a word in the dictionary, so yes, use the hyphen.
You typically need only capitalize after sentence-ending punctuation, which a hyphen is not.
no
No.