Thank you for answering all my questions,since you are too busy to read the post you have answered, and you don't read the private messages , so I have to post a new thread to draw your attention,=)
This forum is a place where questions are submitted so that anybody can respond. Addressing a question to just one person deprives you of the chance of other, and possibly more correct, responses.
Also, those of us who answer questions do so in our free time, as and when we wish. If we do not respond to a question it may be that someone else has given an adequate response, that we don't know the answer, or simply that we are more interested in other questions.
1. All the grammar books in China indicate that the three expressions are all correct.
"This room is twice as big as that one."
"This room is twice bigger than that one."
"This room is twice the size of that one."
I have already answered this in the thread. Please do not start separate threads for the same question..