Css 为什么我的文字没有环绕图像？

这是我的密码。。。我希望图像向左浮动，文本换行。 这是我的密码

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            <img src="~/Images/COWH/Case Study Images/Broward County FL - Tree Planting at LLMS - 4-29-17 - Patrick Fitzgerald.jpg" class="pull-left img-responsive" />


            <h4>Broward County, FL</h4>

            <p>
                Broward County, the nation's eighteenth largest county, with a population of 1.7 million people, is located in Southeast Florida and is bordered by the
                Everglades and the Atlantic Ocean with endless opportunities for viewing and interacting with wildlife. While 2/3 of the county is located in the
                Everglades, the remaining urban area is a diverse, vibrant, urban community with parks, beaches, and green space
            </p>

            <p>
                Gardening for wildlife, protecting natural areas, and improving flyways for migratory wildlife are a priority for the County Commission, which formed the
                NatureScape Broward program in 2003 to encourage residents and businesses to create wildlife habitats. Broward County was certified as a Community Wildlife
                Habitat in 2005, and encourages its 31 municipalities to do the same. Successes include the re-establishment of the endangered Atala butterfly population,
                increased sea turtle nesting, and the first school district in the nation to be certified as a Schoolyard Habitat.  Perhaps the best example of achievement
                is the continued interest of residents to add native plants, protect water quality, and preserve their unique ecosystems for future generations.
            </p>

            <p>Diana, Broward County NatureScape Leader and Community Wildlife Habitat Team Leader</p>
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佛罗里达州布劳沃德县

布劳沃德县是美国第十八大县，人口170万，位于佛罗里达州东南部，与佛罗里达州接壤
大沼泽地和大西洋为观赏野生动物和与野生动物互动提供了无限的机会。而该县的2/3位于
大沼泽地，剩余的城市区域是一个多样化、充满活力的城市社区，有公园、海滩和绿地


野生动物园艺、保护自然区域和改善迁徙野生动物的飞行路线是成立该委员会的县委员会的优先事项
2003年，自然景观布劳沃德计划鼓励居民和企业创造野生动物栖息地。布劳沃德县被认证为社区野生动物保护区
并鼓励其31个城市也这样做。成功包括重建濒危的阿塔拉蝴蝶种群，
增加海龟筑巢，成为全国第一个被认证为校园栖息地的学区。也许是最好的成就范例
增加本地植物、保护水质和为后代保护其独特的生态系统是居民的持续兴趣。

戴安娜，布劳沃德县自然景观负责人和社区野生动物栖息地团队负责人

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结果也是这样：

只需指定图像的特定宽度和高度，您的内容就可以获得一些空间

img{
   width: 250px;
   height: 250px;
   margin: 0 10px 0 0;
}

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你能显示CSS吗？你包括引导吗？引导网格正在工作CSS正在引导这工作，非常感谢！！我快到最后期限了。