Income tax class 숙제인데  다음 문장들이 명확하게 이해가 되지 않아서요.

감사합니다

Gross
income derived by an individual from a trade or business includes gross income
received or accrued  in the taxable year
from a trade or business even though such income may be attributable in whole
or in part to services rendered or other acts performed in a prior taxable year
as to which the individual was not subject to the tax on self-employment income