Devotion and selflessness are the __________ it takes to become such great people as Norman Bethune and Nelson Mandela.
—Why did you eat your words, Billy? — Sorry, dear.But I really forgot where I was _____ to meet you.
Only by shouting at the top of his voice _______.
The old lady had expected to see all her relatives when she was ill in hospital, but none came to see her ______ many of her neighbors offered their help.
It’s important for us to employ a word or a phrase according to the ______ in language studies.
—As we know, you won’t go back to the USA since you have established a research center here.But how long _____ in America? —For almost 10 years.