单选题 My niece has been to Sumatra and Iran as well as all of Europe. By the time she's twenty, she ______ almost everywhere.
  • A. will be
  • B. would have been
  • C. will have been
  • D. would be


【正确答案】 C
【答案解析】[考点] 考查动词时态。
将来完成时与一个表示未来确切时间的某一点连用，可以表示动作到这个点时已经完成，也可以表示一个动作在另一个未来的动作发生之前已完成。by the time常常用来引导将来完成时，故选C。