Because Shanghai has both fresh air and more job opportunities, .后面的分句不用加so了,因为前面已经用了Because,because跟so不能同时出现在同一个句子里（同一个句号里面）.
翻译因为上海不仅空气新鲜而且有更多的工作机会
Because Shanghai has both fresh air and more job opportunities, .后面的分句不用加so了,因为前面已经用了Because,because跟so不能同时出现在同一个句子里（同一个句号里面）.