Several of the administrative participants recognized the support and leadership from their institution's chief executive officers as a serious motivating factor at those moments _________.

单项选择题At that time no one's even studied the problem, _________ tried to do anything about it.

单项选择题Well, really _________ now is start learning what to do with this software and read a lot of tutorials, learn and practice _________ you can.

单项选择题The women ran down to assist them in bringing up their seals; but no sooner _________ the house than a voice was heard in the passage, and a man entered.

单项选择题It was odd that you _________ for Margie's address. I just got a letter from her—the first one since her family moved on August 1 1983.

单项选择题It's freezing outside; you'd better _________ black ice when you drive home.