新概念3 课后练习JOhn put his wallet into microwave oven----
A：to keep i safe B: for keeping safe
C: for the safey D: to be safe keeping
答案是A,可以理解,但是C哪里错了,是要用for its safety吗?听讲解说是结构错了,不太明白,高手解答一下吧,谢谢.
A选项是to keep it safe，打漏了it