【单选题】Advertising first became important in the late 15th century, __ the merchants of the rapidly growing cities and towns needed a way to tell people __ their goods could be bought.
【单选题】In the mid-19th century , the rapidly growing industries were able to _______ hundreds of thousands of immigrant workers who poured into the American cities.
【单选题】Advertising first became important in the late 15th century, __ the merchants of the rapidly growing cities and towns needed a way to tell people __ their goods could be bought.