You _____ be tired; you have been working for so long a time,but he _____ be tired; he has just begun to work.
A lot of lovers chose to get married on Dec. 12, 2012, ________ the date, the month and the year match.
I felt surprised that anyone of his intelligence ________ such an easy test.
We ________ take clean drinking water for granted. One day we may run out of it.
Parents are doing all they ________ to help their children achieve their ambitions.
________ for the fact that she broke her leg, she might have passed the exam.