Four multiplied by three is twelve.multiplyvt.1. 乘,使相乘[(+by/together)]Four multiplied by five is twenty.五乘四得二十。2. 使(成倍地)增加Such examples could be multiplied indefinitely.这样的例子不胜枚举。3. 使繁殖Hot weather multiplied the bacteria in the food rapidly.炎热的天气使食品中的细菌迅速繁殖。vi.1. 增加As we climbed up the mountain, the dangers and difficulties multiplied.我们越向山顶攀爬,危险和困难越是倍增。2. 繁殖Rabbits multiply quickly.兔子繁殖很快。3. 做乘法He learned to multiply at the age of five.他五岁学会做乘法。