What did the dog handlers learn before the searches? A.There was actually no target scent in the search areA. B.Each search area contained three target scents. C.Their dogs were expected to find the scents of red paper. D.Some target scents may be labeled with a special mark.
A.There B. B.Each C. C.Their D. D.Some E.
【参考答案】
D 解析：根据题干中的Before the searches将本题出处定位到第2段第2句。该句用两个that从句......