The sleeping boy is my son.
The excited people rushed into the building.
A lost opportunity never returns.
He is a retired worker.
The girl standing under the tree is my niece.
The building built last year is our library.
This is the question given.
There is nothing interesting.
Most of the people invited to the party were famous scientists
Not receiving any letter from him, I gave him a call.
As I didn't receive any letter from him, I gave him a call.
Given more attention, the trees could have grown better.
If more attention was given, the trees could have grown better. （条件）
Walking along the street, I ran across my old friend.
Bitten by a snake, he was taken to hospital. （原因）。
Though defeated, he didn't lose heart. （让步）
He lay on the grass, looking into the sky. （伴随）
He came running to tell me the good news. （方式）
（Being）Used for a long time, the book looks old.由于用了很长时间，这本书看上去很旧。
Using the book, I find it useful.在使用的过程中，我发现这本书很有用。
When completed, the museum will be open to the public next year.
Having suffered such heavy pollution already, it may now be too late to clean up the river.