.I soon found that the work I was doing had already been done by someone else - ________, I was wasting my time.
How do you _______it and what should you ________it?
-Do you know our hometown at all?-No, this is the first time I _______ here.
-Have you finished your experiment report, Jane?-Oh, my God. I’ve _______ forgotten all about that.
--What can I do for you,sir? ----I”d like to see the manager ________of sales department.
The scientist decided to devote his life to ____ pollution from ____ again.