来自担忧客户的电话一直源源不断。

There has been ___a steady ___stream ___of phone calls from worried customers.

我生病期间，访客不断。

I had ___a constant ___stream ___of visitors while I was ill.

在老城区，游客可以观看源源不断的过路人。

In the old city, visitors can watch ___an endless ___stream ___of passers-by.