最美情侣中文字幕电影,在线麻豆精品传媒,在线网站高清黄,久久黄色视频

歡迎光臨散文網(wǎng) 會員登陸 & 注冊

GM_002系列托福綜合寫作

2023-03-08 14:45 作者:TF真題收納  | 我要投稿


GM_002

?

綜合寫作

?

Dental amalgam has been for decades and remains today the most commonly used material in dental repairs such as tooth fillings. However, it is a mercury alloy, meaning that it is a mixture of mercury and other metals. It is well documented that direct exposure to mercury has a toxic effect, but there are many experts who believe that mercury may be dangerous even in alloy form. For this and other reasons, mercury should be prohibited from use in dental repairs.

Health Concerns

First, mercury has long been known to have adverse effects on human health. Some experts consider it possible that the small amounts of mercury in the amalgam used to repair a tooth can, over long periods of time, enter a person’s central nervous system, potentially causing neurological, psychological, and immunological problems.

Pollution Problems

Second, waterways in the United States and the wildlife in them are being harmed by mercury contamination. The escape of amalgam waste from dentists’ offices is responsible for a large percentage of the mercury contamination in waterways in the United States. Amalgam waste is washed down the dentists’ office drains and into sewer systems that empty into lakes, rivers, and other bodies of water. Ultimately, the mercury in this amalgam ends up at the bottom of lakes and rivers; there, bacteria transform it into methylmercury, a form of mercury that is especially harmful to wildlife.

Alternatives Available

Third, dental repairs can be made without exposing people and animals to the dangers of mercury. Alternative materials such as gold, porcelain, and resin are widely available. Many dentists are now recommending that those or other materials be used instead of amalgam.

聽力文稿
見評論區(qū)。

GM_002系列托福綜合寫作的評論 (共 條)

分享到微博請遵守國家法律
临江市| 拉孜县| 康乐县| 慈利县| 无锡市| 秭归县| 临颍县| 武清区| 巴彦淖尔市| 贵定县| 长汀县| 辽中县| 平陆县| 游戏| 镇原县| 固原市| 吉隆县| 吐鲁番市| 贺兰县| 岑巩县| 银川市| 岳普湖县| 大名县| 盱眙县| 普兰县| 四子王旗| 永靖县| 福贡县| 科技| 通江县| 公安县| 泰来县| 石首市| 油尖旺区| 宁津县| 满城县| 曲沃县| 铁岭市| 韶山市| 宜兰县| 康保县|