如图，点P是以O为圆心，AB为直径的半圆上的动点，AB=2，设弦AP的长为x，△APO的面积为y，则下列图象中，能表示y与x的函数关系的图象大致是 (   )

B

Dear Tom,

    Thanks for your letter. Do you want to know about my evening? Well, I usually get home from work at 6:00 p.m. I cook dinner for my family—my parents, my sister, and my brother. After dinner I usually watch TV, play computer games or play chess. I like playing chess because my father works in a chess club. I take a shower at around nine o'clock and then go to bed at around nine thirty. Sometimes I read some books because I can learn something about my work. How about your evening? Write to me soon, please.

Best wishes,

Victor