If this dictionary is not yours, _____ can it be?

Various summer camps being available, we can choose    based on our own interest.

Most people felt __________ regrettable that Yaoming retired from the NBA. 
A. one          B. this         C. it           D. what

_______ is known to us all that the 2010 World Expo took place in Shanghai.

People are advised not to drive after drinking, but __ seems not to help a lot.

Use your head; nothing taught by others can have the same effect on you as _________learned by yourself.

The computer made in the USA is cheaper than___ made in Germany.

He soon made _____ clear why he had asked for a conference.

—Which of the two books will you buy?
— I’ll buy _____ of them, because I’m not interested in them.

I’ve always wanted a MP5 and I’ve just saved enough money to buy_____.