单项选择题
All the traces are（）old ones.
A.Clear B.Evident C.Obvious D.Apparently
单项选择题 A VESSEL，OTHER THAN A RESCUE UNIT，DESIGNATED TO CO-ORDINATE SURFACE SEARCH AND RESCUE OPERATION WITHIN A SPECIFIED AREA is known as（）.
单项选择题 （）is not a search pattern.
单项选择题 （） is not a search manual.
