患儿女，10岁。因双眼视力逐渐下降2年来就诊。无夜盲史。检查：双眼视力为0.1，验光结果：OD：-1.5DS、OS：-1.75DS，双眼矫正视力0.2；外眼正常，屈光间质透明，眼底检查未见异常。
主要考虑的疾病是（提示：假如闪光视网膜电图检查记录无波形。）（）。
A.视网膜色素变性
B.Stargardt病
C.视锥细胞营养不良
D.结晶样视网膜色素变性
E.Best氏病
F.格子状色素上皮营养不良
参考答案：B, C
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| Do you know what the White House is? Perhaps some of you ① , while (而) some don't. The White House is the ② where the President (总统 ) of the U. S. A lives. It is ③ Washington D.C. It is really ④ . But do you know ⑤ the White House is white? The story ⑥ back to 1812. That year Britain was at war with ⑦ . The British soldiers (士兵) captured (占领 ) Washington, ⑧ some buildings including the President's house were set on ⑨ . In 1814, ⑩ hide the marks (痕迹 ) of the fire, the brown stone walls of the President's house were painted white and it has been called the "White House" since then (从那时起). |
| （ ）①A. do （ ）②A. room （ ）③A. at （ ）④A. red （ ）⑤A. what （ ）⑥A. comes （ ）⑦A. America （ ）⑧A. but （ ）⑨A. fire （ ）⑩A. on a visit to | B. are B. house B. of B. brown B. how B. goes B. Russia B. or B. water B. on their way to | C. is C. family C. in C. green C. why C. runs C. Canada C. and C. rain C. in order to (为了) | D. does D. city D. from D. white D. where D. takes D. France D. then D. war D. as |
