题目

 The part the king gave to his elder daughter is equal in size and value what he gave to the younger daughters.  A. in                    B. of C. to D. with 答案：C如图中是抛物线形拱桥，当水面在n时，拱顶离水面2m，水面宽4m，水面下降1m，水面宽度增加多少？