It should be hyphenated.
It should be hyphenated if used as a noun clause, but not if used as an adjective
It should be hyphenated.
Yes, "half-page ad" should be hyphenated to show that "half" and "page" are acting together as a compound adjective to describe "ad."
Self-made should be hyphenated.
Pre construction - two words not hyphenated.
No, "two thirds" should not be hyphenated. It is a compound adjective that functions as a single unit modifying a noun.
No, the phrase "hour and a half" is not hyphenated when used in a sentence. It should be written as three separate words. However, when used as an adjective before a noun, it can be hyphenated, like in "an hour-and-a-half meeting."
Underdeveloped should be written as one word, not two words or hyphenated. I hope this answered your question. :)
it should be hyphenated: close-out
Roller-skate, as a verb, should be hyphenated. Roller skate, as a noun, is not.
Fine-tune is an 8 letter hyphenated word. High-tech, half-mast, half-moon are additional hyphenated words.