When I ... it ... yesterday.

The correct answer is: woke up, rained. Here's why: The sentence requires the past simple tense for both actions because they happened and finished in the past (yesterday). 'Woke up' is the past tense of 'wake up', and 'rained' is the past tense of 'rain'. Therefore the completed sentence is: 'When I woke up, it rained yesterday.'.