He is said___________a book on the history of Chinese tone bridge , but I don’t know if he has finished it. A. to have written B. to be writing C . having writing D writing
Have your working conditions improved? ---No, ______than before, I’m afraid.
The task is too much for me, so I can’t carry on ______any longer. I must get some help.
I haven’t seen______ this since I collected stamps.
—— What do you think of the concert?—— Oh, it was______success.
The plane flew smoothly ______ in the sky and people spoke ______ of theexperienced pilot.