Barack Obama has taken personal blame ________ the security failures which led ________ the attempt to blow up a plane on Christmas Day.
Over 80 percent of the population _____ workers.
A professor and writer ____ present at the meeting last night.
The boy at the back is the only one of the students who _____ from Africa in our school.
It is not I but you who ______ the first to run to the goal in that competition.
Each boy and each girl ______ a new book.