Past Perfect. This is usually regarded as a narrative tense. It occurs especially in the context of telling stories. Past Perfect indicates a point in the past which occurred before another moment in the past. The furthest point in the past is Past Perfect. The more recent (but still past) point is Past Simple. In the sentences choose the correct form of the verb - Past Perfect or Past Simple. 

Mary ___ her homework before she came to school and was worried. (do)

___ you ___ the instructions before you tried to assemble the shelves? (read)

Igor ___ to buy flour and so he couldn't make a cake. (remember)

Mary and Jim arrived in the hotel late at night. Mary told Jim it wasn't what she ___. (expect)

James was so talented he ___ 5 novels before he reached the age of 20. (publish)

Let me tell you a story. Sherlock Holmes ___ to bring his magnifying glass and had to borrow one from Watson. But, they found the criminal all the same. (forget)

___ you ___ of this band before you went to see them? (hear)

They ___ Jim for ages and were very worried. (see)

___ Jonathan ___ his family what to expect before they moved in to their new house? (tell)

The students ___ the classroom before the start of the term. (tidy up)