A case in America

3.A successful case study
American society began aging in the 1960s and now the elderly account for about 13% of the American population. The American pension system and real estate industry has /have become increasingly stable for half of a century (Li, 2008). There is a successful case of /the retirement community called “Sun City Center” in Arizona which built on a large scale by Del Webb (你这句需要解释一下。。。感觉没说完）. This project has 5 main advantages and /each advantage will be analyze /analyzed individually.
(1) Strict management
people who has /have the qualifications to live in Sun City Center must be over 55 years old. This rule could prevent the possibility of investors occupied /occupying resources and it also helps protect the rights of /the elderly people.
(2) Barrier free design
Sun City Center has the /a barrier free design such as the /that includes blind lanes, disabled access, and the /a safe separation between people and vehicles. It is quite necessary for the elderly that with reduced mobility. (最后一句不流利） These measures are quite necessary given the elderly have reduced mobility.
(3) Location
Sun City Center is located in the place which has a comfortable climate with especially adequate sunshine. It is calculated that the total daylight hour is about 312 days annually there are 312 days of annual daylight hours. Besides, it is near the Lake Pleasant Park which has wonderful scenery. The surrounding is quite suitable for the elderly.
(4) Architectural Diversity
There are dwellings and some other facilities for leisure, entertainment, commerce, as well as drop-in centers and elderly care for the elderly community. Dwellings vary in size, function, and design, .  /It includes apartments, houses and /a lifestyle center which could fully /meets the various needs of different elderly.
(5) Medical Service
In Sun City Center, health and medical conditions have achieved the an advanced level (改完之后还是怪怪的。可能需要你解释一下）. The community offers expert consultation and the medical staff will regularly check the elderly health door to door regularly, especially the psychological service to make their life longer (这句不太清楚。。。你是要强调心里服务给他们带来更长的生活吗？需要解释）.
Above all, Sun City Center proves that it is feasible leading real estate to develop communities for the elderly provides lessons for China (抓不到重点。可以解释吗？）. However, China should consider its local conditions. As the designer said, “Our country is aging heavily and what we want to do is to have more vitality, more activity, and more than what we are used to in our country. (Rubiano & Chan, 2010).” Therefore, developing communities is not only to build houses. Good services such as care services especially are also needed especially care services.

Overall not bad, but you need be really careful about a few things:

1. Verb tenses and pluralization of objects (when to use "has" versus "have"). 

2. When to use and not use punctuation like commas ",".

3. A few sentences were a little bit too complex and seemed to include multiple points. I wasn't able to guess the meaning. If you have the time, would you explain them in Chinese so I can better help you translate?