the eighth day of the month / eight days

the ninth day of the month / nine days

the seventh day of the month / seven days

work done for free, unpaid work, uncompensated work / work done in vain, work with no favorable end result

to work for free, to work without pay or other compensation / to work in vain, to work with no favorable end result

(archaic, grammar) any word that declines or conjugates / (archaic, grammar) more specifically, a verb

each person

middle, medium / average; neither good nor poor / during; being in the process of doing / second volume of a three volume set

China or Chinese; Sino- (prefix)

being in the process of doing