It is the test system, _______ the teachers, that is to blame for the heavy burden of middle school students nowadays.
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.
The old man’s _______ pity on the snake led to his own death.
________ many times, but he still could not understand it.