关于老年性白内障成熟期的描述，错误的是（）
A.视力明显减退至眼前指数或以下
B.晶状体完全混浊
C.虹膜投影存在
D.是白内障摘除的最佳时机
E.以上描述均错误
参考答案：C
解析：本题要求考生了解老年性白内障各期的特点，在成熟期时患者的晶状体全部混浊，用斜照法不能看见深层的混浊皮质，故不出现虹膜投影（新月形暗影），虹膜投影是白内障膨胀期的特征性表现。
Complete the following passage by using the words in the box．Each word can only be used once．Note that there is one word more than you need.
Why is unhappiness less influenced by 小题3:? When we are happy, we are more responsive to people and keep up 小题4: better than when we are feeling sad． This doesn’t mean, however, that some people are born to be sad and that’s that．Unhappiness may be related to genes, but this inherited trait can be influenced by 小题5: choice．You can increase your happiness through your own actions. In a whole小题6: of experiments by psychologists John Reich and Alex Zautra at Arizona State University, they asked students to select their favorite activities from a list of everyday pleasures－things like going to a movie, talking with friends and playing cards. Then the researchers 小题7: some of the students in the experiment to increase the number of favorite activities the participated in for one month (the participants in the study 小题8: as controls (对照组) and did not vary their activity level)．Result: Those who did more of the things they enjoyed were happier than those who didn’t．The conclusion, then, is that the pleasure we get from life is 小题9: ours to control. |