一起答
单选

Scientists estimatethatabout 530,000 objects, too small to detect with radar, ________theEarth too.

  • A.being circled
  • B.are circling
  • C.are to be circling
  • D.are being circled
试题出自试卷《2016年广东成考学位英语真题及答案》
参考答案
查看试卷详情
相关试题