In the 21st century, all nations must take their ________of responsibility for the global safety.

The Iranian government is accused of __________ some terror organizations in the Middle East by the United States. [ ]

Who do you think is to blame for the boy’s behavior, Mary or her parents— We all think it is Mary as well as her parents that ______ for their son’s bad performance at school.

brought up in Los Angeles, Steven Davidson spent his whole life in New York．

I wonder _______. —By searching the Internet.