In our class, when the bell rang and the teacher closed his book, it was a ______ for everyone to stand up.
This church is as old as, if _____ than, that one.
In that month, he earned as much as, if ____ than, $40 000.
The problem is not _____ easy. Think _____ over.
It is so difficult a problem that _____ student in this class _____ work it out.
.Please make my excuse at tomorrow's meeting. I've got too much work _____.