There is a hyphen in phrases like "100-year", because they precede whatever they are modifying, like a "100-year flood". In general, two-word phrases are hyphenated when they are used as adjectives and precede the term they modify.
No.
Yes
No it doesn't require to be hyphenated.
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.
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.
part before hyphen is model number for 1969 4 hp.
If you're using the phrase as an adjective (example "I hate the end-of-the-year audit!") then it will definitely need the hyphens. Otherwise, the hyphens are incorrect.
B
Four-year should be hyphenated but not institution.
Yes it should be hyphenated.
"Midyear" is typically written as a single word without a hyphen when used as an adjective or noun. However, "mid-year" with a hyphen can also be acceptable in some contexts, especially when it precedes a noun. Overall, the choice between the two can depend on style guides or personal preference, but "midyear" is more commonly used.
There was no year zero century or year zero. 1 AD immediately followed 1 BC. The first century AD immediately followed the first century BC. There was no century between them.