but it took some time before I()for myself what they were like.

but it took some time before I()for myself what they were like.

答案不对。
应该是B
find out sth/丛句， 意思是：搞明白，搞清楚，发现（通过努力发现）等
这里意思：我花了一些时间才自己搞清楚他们的真面目。
A的find sth 指找到某东西，某人等，不涉及内涵等需要拨开现象看本质的东西。