Simple Past vs Past Perfect Tenses

Fill in the blanks with Simple Past or Past Perfect Tenses.

When I (1) (arrive) home last night, I (2) (discover) that Jane (3) (prepare) a beautiful candlelight dinner.
When I (4) (turn) the radio on yesterday, I (5) (hear) a song that was popular when I was in high school. I (6) (not hear) the song for years, and it (7) (bring) back some great memories.
Last week, I (8) (run into) an old friend of mine. We (9) (not see) each other for years and both of us (10) (change) a great deal.
When Emilio (11) (enter) the room, I (12) (not recognize) him because he (13) (lose) so much weight and (14) (grow) a beard. He (15) (look) totally different.
When Oprah Winfrey (16) (get) her own TV show in 1986, she (17) (work) as a news reporter for a long time.
In 1976, 60% of families (18) (be) couples with children but by 1996, this (19) (fall) to 51%.
Several senior employees (20) (leave) the company by the time the new manager (21) (arrive) last week.
Until the new software (22) (purchase), the staff (23) (struggle) to keep the accounts up to date.
I (24) (see) that movie three times last year
When my supervisor (25) (pop in) my office the other day, I (26) (work) on the project for nearly three hours.

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