Turn-yielding cues relinquish control of the conversation. We might look at the listener more steadily or remain silent for a noticeable period to indicate that we are finished making a point. Turn-maintaining and turn-yielding may also be expressed explicitly. It's a conversational turn.
The adverb in this sentence is "<u>yesterday</u>". It is an adverb of time and it means the day before today.
Adverbs describe the the action of the verb. Adverbs of time indicate when the action happened, the length of the event, and the frequency of the episode.
