问题
选择题
Although medical science________control over several dangerous diseases，what worries us is that some of them are recurrent.
A．achieved
B．has achieved
C．will achieve
D．had achieved
答案
答案：B
答案 B [句意：尽管医学已经成功地控制了一些危险的疾病，但令我们担心的是，其中有些疾病还会反复发作。根据句意可知说话者谈论的是从过去延续到现在的情况，故用现在完成时态。]