China has changed a great deal in the past 20 years.
Where have you put the dictionary? I can't find it anywhere.
I have watched him appear on TV several times.
I have been working for five years.
It has been raining since last Friday.
Jim has been ringing John every night for the last week.
I have painted this room.（I’ve finished painting it.）
I have been painting this room.（I haven’t finished painting it.）
He’s run three miles. (the result: He’s covered the distance of three miles.)
He’s been running for an hour. (the activity and its consequences: This is what he’s been doing for the last hour and why he is exhausted now.)
I’ve posted a dozen postcards, but received none.
I’ve read this book several times.
I’ve been posting postcards since early December.
You have been disturbing me.
I’ve known that for a long time.
The strike has lasted six months.
They have been working this term.
They have worked very well this term.