The combination of parties to form a new government tried out to be ______ failure, but as we know, success often comes from _____ failure.
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.
We're leaving at six o'clock , and hope _____ most of the journey by lunch time .