The students _____ £50 a year to cover the cost of books and stationery.
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 _____.
Our math teacher, however, _____ speak English well.