One of the most important questions they had to consider was__________ of public health
I'd like to take________of this opportunity to thank you for your help.
The head of the company promised to deal with matters of this sort________he returned to his office.
I was not________ that I had cut myself until I saw the blood all over my hand.
—Why do you choose to work in an international travel agency?—Well,you know,English is my ________,so it is my best choice.
The idea for the new plan came to his mind,________ to his experiment in the lab.