题目

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。Though most big companies begin as small businesses, not all small business owners are entrepreneurs(企业家). If we look【1】 (much) closely at its definition, we can find three common features.Creating. Entrepreneurship generally means offering a new product, applying a new technique or technology, 【2】 (open) a new market, or developing a new form of organization for the purpose of producing a product.Running a business. A business uses resources 【3】 (produce) goods or services. Entrepre杨辉是我国南宋末年的一位杰出的数学家。在他著的《详解九章算法》一书中，画了一张表示二项式展开后的系数构成的三角图形，称做“开方做法本源”，现在简称为“杨辉三角”，它是杨辉的一大重要研究成果。我们把杨辉三角的每一行分别相加，如下： 1 ( 1 )1 1 ( 1+1=2 )1 2 1 (1+2+1=4 )1 3 3 1 (1+3+3+1=8 )1 4 6 4 1 (1+4+6+4+1=16 )1 5 10 10 5 1 (1+5+10+10+5+1=32 )1 6 15 20 15 6 1 (1+6+15+20+15+6+1=64 ) ……写出杨辉三角第n行中n个数之和等于______．