In order to find the missing child,villagers（）all they can over the past five hours.had done/have been doing

In order to find the missing child,villagers（）all they can over the past five hours.had done/have been doing
In order to find the missing child,villagers（）all they can over the past five hours.
had done/have been doing

In order to find the missing child,villagers（）all they can over the past five hours.had done/have been doing
have been doing
现在完成进行时~有持续做下去的意思
为了找到丢失的小孩,所有村民都找了五个小时了（还可能继续找下去）

have been doing
over the past five hours.这个短语要用现在完成时，所以只有选后者

have been doing