She writes ___ from time to time.
--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.
Tom kept silent about the accident _________ lose his job.
Iraq has ______ too many wars since 1990, making his people _______ a lot.
As is known to all, China _______the group of developing countries.