Occasions are quite rare ____ I have the time to spend a day with my kids.
The black teacher set a good example _____ all the rest of the group, ____ all peace-loving people.
Finally they arrived at a place ________ sold cigarettes and other small articles.
When _______ America and Britain, this famous writer said that the same language _____ the two people.
All the elder people ______ at the party were those _____involved in (参与)community service.
In the past, ice used to ______ used to ______ the air in a room.