单选题 ______ no gravity, there would be no air around the earth, hence no life.
  • A. If there had been
  • B. If there was
  • C. Had there been
  • D. were there
【正确答案】 D
【答案解析】[解析] 本题考查的主要是虚拟语气，如果在含虚拟语气的条件中，if被省略，则应把were移至主语之前。