US President Barack Obama is expecting the economy to show some _________ of recovery.
The situation in the Middle East is so ______ that we have to be ______ when dealing with the hostage issue.
I think it ______ that one have a good command of English if one wants to be engaged in international trade.
It was on May 12, 2008 ______ the Wenchuan Earthquake happened.
Mother told me ______ near the river.
His friends ignored his advice, ______ they knew it to be helpful.