单选题
Without air or water, there ______ no life on earth.
A. is B. will be C. has been D. would be
【正确答案】
D
【答案解析】[解析] 介词without引导的短语在一定的上下文中可以起一个虚拟条件从句的作用，相当于if there were no...或(以人作主语)if...had not...，如：I should have been badly off without your friendship.