(37秒到1分20秒）Now, part of the reason for this is that?we’ve invested a huge amount in nuclear deterrents.?But we’ve actually invested very little____________.?We’re not ready for the next epidemic. A.surveillance B.in a system to stop an epidemic C.medical treatment D.in developing vaccines

(37秒到1分20秒）Now, part of the reason for this is that?we’ve invested a huge amount in nuclear deterrents.?But we’ve actually invested very little____________.?We’re not ready for the next epidemic. A.surveillance B.in a system to stop an epidemic C.medical treatment D.in developing vaccines

正确答案：B