Can you tell me where I can buy some medicine?

Could you please tell me when he left for Japan?

Could you tell me where we could go next?

Do you know where I can get some money?

Look at these sentences

由 wh- 引导的宾语从句

* 连接词： 原先的疑问词 * 语序： 陈述语序 * 时态

When did he leave for Japan? Could you tell me?

Could you tell me when he left for Japan?

陈述语序

主句为一般过去时，从句进行相应的变化