Sandy could do nothing but _____ to his teacher that he was wrong.
Judging from her________,she must be from Shandong Province,but I don't know which city.
(2012年浙江卷,2)The development of industry has been ________ gradual process throughout ________human existence,from stone tools to modern technology.
It is useful to be able to predict the extent _______which a price change will affect supply and demand.
In the dark street,there wasn't single person _______she could turn for help.
(2012年南京高三模考)If something is “dog-eat-dog”,it is a situation ________people have to take care of themselves and look after their own interests.