问题补充:
The milk must be preserved at this temperature until it .
A. will process
B. is processed
C. has processed
D. had been processed
答案:
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。