We have been eating since it started to rain

She has written for 30 minutes

They have been studying Eg since they were in grade 3

We have been chatting on the phone since it began to rain

She has been doing the housework since she got home

He has career as a teacher for 20 years

When did you wait for the bus?

He began to talk two hours ago

Sam has been keeping a diary since 1997

She started to teach in this area since she was 25

S+started/began+Ving+time ago=S+have/has +been + Ving+for/since time

S+started/began+to V+time ago=S+have/has+V3/ed+for/since time

For+khỏang thời gian

Since+mốc thời gian