当a+b=3，x-y=1时，代数式a2+2ab+b2-x+y+1997的值是（ ）。
2005
— Imagine you are outside when _____ earthquake comes. What should you do?
— Go to _____ open space away from buildings or trees. [ ]
A. the; the
B. the; an
C. an; the
D. an; an
