The milk must be preserved at this temperature until it .
A. will process
B. is processed
C. has processed
D. had been processed
网友回答
A. will process
(答案→)B. is processed
C. has processed
D. had been processed
解析：考查时态语态：until引导的时间状语从句，主句用的是情态动词，从句不能用将来时，用一般现在时，而且milk和process是被动关系，用一般现在时的被动，句意：牛奶必须在这样的温度被保存，直到被加工。选B。