GRAMMAR

If the Past Perfect is not referring to an action at a specific time, Past Perfect is not optional. Compare the examples below. Here Past Perfect is referring to a lack of experience rather than an action at a specific time. For this reason, Simple Past cannot be used.

Examples:

She never saw a bear before she moved to Alaska. Not Correct

She had never seen a bear before she moved to Alaska. Correct

ADVERB PLACEMENT

The examples below show the placement for grammar adverbs such as: always, only, never, ever, still, just, etc.

Examples:

You had previously studied English before you moved to New York.

Had you previously studied English before you moved to New York?

ACTIVE / PASSIVE

Examples:

George had repaired many cars before he received his mechanic's license. Active

Many cars had been repaired by George before he received his mechanic's license. Passive