1. It was a time when the killer whales, or “killers” as they were then called, helped the whalers catch the baleen whales that were on their annual migration. 那个时期，虎鲸（当时被称为“杀手”）帮 助捕鲸人在每年须鲸迁徙时捕捉须鲸。

It was a time when… 此处when所引导的是__________。

定语从句