问题补充：
Food safety is important. Rules to stop people from food pollution.
A. must make
B. must be made
C. can’t make
D. can’t be made
答案：
A. must make
(答案→)B. must be made
C. can’t make
D. can’t be made
解析：考查含有情态动词的被动语态的基本构成，情态动词+be+过去分词，句意：食品安全是重要的，必须制定规则使人们远离食品污染。Rule和make是被动关系，用must be made，选B。
