如图所示为水平面内振动的弹簧振子，O是平衡位置，A是最大位移处，不计弹簧质量和小

政府贷款的期限短、利率低。

在液压系统中，为了提高液压缸回油路的压力，增加进给运动的平稳性，在液压缸的回油路上设置（）。

【说明】 著名的四色定理指出任何平面区域均可以用4种颜色着色，使相邻区域着不同的颜色。本程序对给定的区域图找出所有可能的不超过4种颜色的着色方案。 【函数】 # include ＜stdio.h＞ #define N 10 /*要着色的N个区域*/ void output(int color[]) /*输出一种着色方案 color[i]的值为区域i所着颜色*/ { int i; for (i=0; i＜N; i++) printf("%4d", color[i]); printf("\n"); } int back(int *ip, int color[j] /*回溯*/int c=4;while (c==4){ if (*ip＜=0)return 0: --(*ip);c= (1) ; color[*ip]=-1;}return c; } /*检查区域i，考查c种颜色的可能性 */ int colorOK(iht i, int c, int adj[][N], int color[]) { int j; for(j=0; j＜i; j++) if ( (2) ) return 0; return 1; } /*为区域i选一种可着的颜色*/ int select(int i, int c, int adj[][N], int color[]) /*寻找各种着色方案 adj[i][j]=1表示区域i与区域j不相邻*/ { int k; for (k=c; k＜=4; k++) /*4种颜色*/ if (colorOK( (3) )) return k; return 0; } int coloring(int adj[][N]) { int color[N], i, c, cnt; for (i=0; i＜N; i++) color[i]=-1: i=c=0; cnt=0; while (1) [ if ((c= (4) )==0) { c=back(&i, color); if (c==0) return cnt;} else {(5) ;i++;if(i==N) {output(color);++cnt;c=back(&i, color); }else c=0; } } } void main() { int adj[N][N]={ {0, 1, 0, 1, 1, 1, 1, 1, 1, 1}, {1, 0, 1, 1, 0, 1, 1, 1, 1, 0}, {0, 1, 0, 1, 0, 1, 1, 0, 1, 1}, {1, 1, 1, 0, 1, 1, 0, 0, 1, 1}, {1, 0, 0, 1, 0, 1, 0, 0, 0, 0}, {1, 1, 1, 1, 1, 0, 1, 0, 0, 1}, {1, 1, 1, 0, 0, 1, 0, 0, 1, 0}, {1, 1, 0, 0, 0, 0, 0, 0, 1, 1}, {1, 1, 1, 1, 0, 0, 1, 1, 0, 1}, {1, 0, 1, 1, 0, 1, 0, 1, 1, 0} }; printf("共有%d 组解.\n", coloring(adj));

The owner (buyer)of a project usually has the right to direct changes to the scope of work while the project work is being accomplished. Often, the owner will orally request a change and insist that the change be initiated immediately without the normal documentation (e. g. a change order). When the change is initiated without documentation, ______ .

A．the owner assumes all responsibility for paying for the change although the owner may at a later not want the change

B．the owner assumes responsibility for one-half the cost of the change until the documentation is completed and all at the same time

C．the project manager assumes all risk for the change, if initiated, until the documentation is received

D．the project manager assumes only the risk of misinterpreting the owner’s oral change directive, while the owner assumes responsibility for paying for the request change

机械整平堤顶时，适宜碾压方法不包括（）。

A.平碾碾压

B.气胎碾碾压

C.不开震动碾碾压

D.震动碾压