问题补充：
There are some seemingly insignificant matters that, when in time, can become bigger ones later on.
A. not dealt with
B. not being dealt with
C. not to be dealt with
D. not having been dealt with
答案：
(答案→)A. not dealt with
B. not being dealt with
C. not to be dealt with
D. not having been dealt with
解析：考查时间状语从句的省略：句意：又很多看似不重要的事情，当不被及时处理的时候，就可能变成更大的问题。这里是省略句，完整的是：when some seemingly insignificant matters are not dealt with in time当主从句的主语一致的时候，可以省略从句的主语和be动词，选A。
