何谓视疲劳？试述视疲劳的症状及病因。
参考答案：视疲劳是以病人眼的自觉症状为基础，眼与全身因素和精神（心理）因素互相交织的综合征。（1） 症状： ① 视力障碍；② 肌源性眼痛；③ 眼睑及结膜长期慢性刺激，充血，慢性炎症，睑缘炎反复发作；④ 全身症状。（2） 病因： ① 环境因素；② 眼部因素：屈光不正，眼肌功能障碍，调节障碍，集合功能差，两眼视网膜成像不等，双眼单视功能有障碍，屈光间质混浊；③ 全身因素。
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2. We have lunch in the _____________________________. 3. We play football on the ___________________________. 4. We water the flowers in the _______________________. 5. We study English in the __________________________. |
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| It is interesting to visit another country. But sometimes there are problems when we don't know the 1 very well. It may be 2 to talk with the people there.We may not know how to use the telephone i n the country we are 3 . We may not know how to buy the things we 4 . In a strange country we might even not know where to eat or what to order in a 5 . It's not easy to decide 6 money you should give to the waiters and the taxi drivers as a tip(小费). When we need 7 ,we might not know who to ask for help. It is not pleasant to have an 8 like that. Maybe we can 9 what to do and what to say in a short time. But when we start to enjoy the life in another country, we have to 10 . And when we get back home,we will be sorry for the visit. | ||||
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