I've achieved a lot in my study, thanks to ____ who helped me.

 To her joy, Della earned first the trust of her students and then ____ of her colleagues.

—What about asking these new graduates to take on the task?—I m afraid not．While they are energetic and ambitious, _____ of them seems to be suitable for this demanding job．

I’m moving to the countryside because the air there is much fresher than ________ in the city.

—Is this film interesting?—Yes, but I am sure it won't interest________.