After the Six­Party Talk in Beijing, an agreement was reached _____that North Korea would abandon（放弃）_____ nuclear weapons.

________ his lessons , he failed in the exam.

________, you need to give all you have and try your best.

Victor apologized for ________ to inform me of the change in the plan.

She had her watch           on the bus．

The math problem seems very easy, but in fact it is very difficult_______.

-----What did you think of Mount Tai?
------Wonderful. It’s worth ______once again.

－What will today’s talk be about?
－In the lecture ______, the professor will tell us something about modern English usage.

—What made little Tony so unhappy and cry in his room?
— ______ to go hiking with his brother.

Every evening after dinner, if not ______from work, I will spend some time _____ my dog.