请用计算器求数据271,315,263,289,300,277,286,293,297,280的平均数,结果是____
李敏的爸爸做服装外贸生意,近年来,他的国外客户越来越多,交易额越来越大。这主要得益于国家实施( )
The deaf people have their own ways _______ with each other.