题目

To ihis spoken English, he oftentalks with foreign people in the park. 答案：【1】improve12．计算sin21°cos9°+sin69°sin9°的结果是（　　）A．$\frac{{\sqrt{3}}}{2}$B．$\frac{1}{2}$C．$-\frac{1}{2}$D．$-\frac{{\sqrt{3}}}{2}$