根据语境，给下面一段话中划线的字注音。

       做事战战惊惊，如履____薄冰的，一定不是李达康这样棱____角分明的人。

函数f（x）=cos²x+$\sqrt{3}$sinxcosx在区间$\frac{\mathrm{\pi }}{6}$，$\frac{\mathrm{\pi }}{2}$的最大值为（　　）

根据短文选择正确答案。

    Li Ming is a middle school student. He is a good boy. Uncle Wu lives next to him. Uncle Wu has no child and can't see anything. He works in the factory near Li Ming's school. He goes to work at 7:30 in the morning and comes home at 4:30 in the afternoon. Li Ming walks to school at 8:00 in the morning and comes home at the same time as Uncle Wu in the afternoon. On weekdays, Li Ming gets up early to take Uncle Wu to the factory. After school he takes him home. On Sundays Li Ming helps Uncle Wu clean the house and do some cooking. Uncle Wu thanks Li Ming very much. He says, “Li Ming is a good boy. He is like my son. ”