过去进行时常见的标志性时间状语主要有：this morning、the whole morning、all day、yesterday、from nine to ten last evening、when、while、at that time等
look-looking cook-cooking read-reading
begin-beginning swim-swimming sit-sitting
tie-tying die-dying lie-lying
this morning,the whole morning,all day,yesterday,from nine to ten last evening,when,while,at that time.
My brother fell while he was riding his bicycle and hurt himself;
When I got to the top of the mountain,the sun was shining.