18. Even though the state has spent ten years and seven million dollars planning a reservoir along the Ubi
River, the project will have to be abandoned as a result of the river becoming so heavily polluted. (A) will have to be abandoned as a result of the river becoming so heavily polluted (B) is to be abandoned on account of the heavy pollution which the river received (C) had to be abandoned because the river had received such heavy pollution (D) has to be abandoned because of the river and its heavy pollution（E） (E) must be abandoned because the river has become so heavily polluted 答案e 明白为什么其他的选项不好，但是e中加了must会不会有什么问题啊？所以权衡了下，我最后选了A | 
