When I tried to find _________that prevented so many people from taking part in the program, it seemed to me that there were two main reasons.
You _____ tell him. He is fully aware of the danger.
_____ his ability of speech, he has made use of each chance.
People pay ______as to the content of your speech.
____ I paid a visit to this scenic spot, I was deeply attracted by its beauty.
I want to be very careful to talk only about ____ we've formally tested.