首先,while不能够引导宾语从句.但是,可以引导【时间状语从句、让步状语从句】.例如：
While he had tried his best,he failed in again in the driving test.【让步状语从句】
While dreams are important in our life,they can also affect our action .【让步状语从句】
Tom was watching TV while his mother was cooking.【时间状语从句】
While you are at the supormarket,please buy me a notebook.【时间状语从句】
可见,while从句的时态不一定都要用过去时.
祝你开心如意!