问题
选择题
Large quantities of polluted water_____ into the sea so that lots of fish died.
A．is flowing
B．was flowing
C．are flowing
D．were flowing
答案
答案：D
quantity作主语时,谓语动词要与quantity的单复数保持一致, 此处quantity为复数，再由后一句的时态可知答案为D。