| 1. Federal authorities involved in the investigation have found the local witnesses are difficult to locate, reticent, and are suspicious of strangers.
(A) the local witnesses are difficult to locate, reticent, and are
(B) local witnesses to be difficult to locate, reticent, and are
(C) that local witnesses are difficult to locate, reticent, and
(D) local witnesses are difficult to locate and reticent, and they are（C）
(E) that local witnesses are difficult to locate and reticent, and they are
be suspicious of 这个短语，be 可以省略么？
不是像be able to 那样子，是整个连在一起的么？ | 
