摘要： Researchers to develop vaccines and this will probably take several months to complete. A. are working B. worked C. will work D. has worked
网址：http://m.1010jiajiao.com/timu_id_3567218[举报]
15. Researchers _______ to develop vaccines and this will probably take several months to complete.
A. are working B. worked C. will work D. has worked
查看习题详情和答案>>Researchers _______ to develop vaccines and this will probably take several months to complete.
A. are working B. worked C. will work D. has worked
查看习题详情和答案>>
15. Researchers _______ to develop vaccines and this will probably take several months to complete.
| A．are working | B．worked | C．will work | D．has worked |