警方成功追踪到了那名失踪儿童，发现他在邻镇。

The police successfully ___traced the missing child to a neighboring town.

调查人员正试图查明抢劫案前嫌疑人的行踪。

Investigators are attempting to ___trace the suspect's movements before the robbery.

你可能需要专家来追踪找到那个电脑病毒的源头。

You might need a specialist to ___trace the source of that computer virus.