Complex sentence: In 1964, the Industrial Union Department of the AFL-CIO pledged to match dollar-for-dollar the expenditure of AFT funds to organize teachers.But by the end of the decade, the union had swelled to more than 400,000 members.
Split into simpler sentences: In 1964, the Industrial Union Department of the AFL-CIO pledged to match dollar-for-dollar the expenditure of AFT funds to organize teachers. But, by the end of the decade the union had swelled to more than 400,000 members.