____to my regret, I am unable to accept your warm invitation.
It never occurred to meyou could succeed in persuading him to change his mind.
_________ from the space, the Great Wall lies in the mountains like a huge dragon.
With so much noise of the traffic, I couldn’t ______ and do my research work.
He found his house broken into and many things stolen _______ his return from office.
He managed what ___a smile of satisfaction though it was an unexpected result that came out..