名词解释：针对相关问题作简明扼要的回答。

[单选题]Shopping habits in the United States have changed greatly in the last quarter of the 20th century. （1） in the 1900s most American towns and cities had a Main Street. Main Street was always in the heart of a town. This street was （2） on both sides with many （3） businesses. Here, shoppers walked into stores to look at all sorts of merchandise: clothing, furniture, hardware, groceries. （4）,some shops offered （5） .These shops included drugstores, restaurants, shoe-repair stores, and barber or hairdressing shops. （6） in the 1950s, a change began to （7） .Too many automobiles had crowded into Main Street （8） too few parking places were （9） shoppers. Because the streets were crowded, merchants began to look with interest at the open spaces （10） the city limits. Open space is what their car-driving customers needed. And open space is what they got （11） the first shopping centre was built. Shopping centres, or rather malls, （12） as a collection of small new stores （13） crowded city centres. 14 by hundreds of free parking space, customers were drawn away from （14） areas to outlying malls. And the growing （16） of shopping centres led （17） to the building of bigger and betterstocked stores. （18） the late 1970s,many shopping malls had almost developed into small cities themselves. In addition to providing the （19） of one stop shopping, malls were transformed into landscaped parks, （20）benches, fountains, and outdoor entertainment. 请在9处填上正确答案（）

[单选题]下列关于资源税纳税义务发生时间的表述，不正确的是（）。

[判断题]跆拳道晋升考核中成绩低于50分将降低考核者的等级或段位.

[问答题]在进行隧道的检查、补漏、衬砌、油刷标志、刨冰及隧道口粉刷装饰，使用高梯搭设脚手架与接触网间距不足2m时，在什么情况下可以作业？

[多选题]土石坝中常见的排水体型式有哪几种。（）

[单选题]如果患者的视力正常，下列哪个神经损伤可能使瞳孔直接对光反射及间接对光反射消失（）

[填空题]工件在定位后，在加工过程中要受到（）

[单选题]最灵活的一种评价方式是（）。

[单选题]穿心莲内酯属于（　　）。

[多选题]在产前诊断中发现下列情况，其中属于遗传代谢疾病的是 【 】