21. August 8th, 2008 is a special day, ____, I think, that will be remembered by the Chinese forever.
A. one B. what C. which D. the one
22. It is not socially ____ for parents to leave children unattended at that age.
A. accessible B. adorable C. adaptable D. acceptable
23. If we go on using energy so wastefully, ____are that our oil wells will be dried up before new energy sources can be found to replace oil.
A. chances B. difficulties C. questions D. problems