Question

How are past perfect and past perfect continuous used in normal conversational English?

Answer 1

past perfect is used to indicate an action completed in the past before some other action.
past perfect continuous is used to to indicate a continuous or repeated action in the past that occurred before some other action.

Explanation:

Examples:

past perfect
`color(white)("XXX")`It had snowed by the timne father got home from work.

past perfect continuous
`color(white)("XXX")`It had been snowing for many hours by the time father got home from work.