Yes, "manager-in-training" should be hyphenated. The hyphen helps clarify that the phrase functions as a single modifier describing someone who is in the process of becoming a manager. Without the hyphen, the meaning could be less clear.
Historically a hyphen was used. In modern times 'cross training' is now presented as two words.
Self-made should be hyphenated.
Pre construction - two words not hyphenated.
It should be hyphenated when it's used as an adjective.
self conscious
No.
roller skates
yes
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.
No, "cross training" does not require a hyphen. It is commonly written as two separate words. However, when used as a compound adjective before a noun, it can be hyphenated as "cross-training."