888 past perfect

By the end of last year, some famous architects in Spain_______ (build) that building.

They _______ (break) all the rules before the class finished.

Before then, no one ___________ (know) the truth.

The meeting had already begun buy the time she _______(enter).

My sister_________ yet_________ (buy) her car when she graduated.

The kids had gone to school when their mother ____________(see) their lunch boxes.

­ Had they eaten before the presentation ___________(start)?