如图所示，单摆摆球的质量为m，摆球从最大位移A处由静止开始释放，摆球运动到最低点

骨盆环的构成结构是（）。

A.髂骨与骶尾骨

B.耻坐骨与骶尾骨

C.髋骨与骶尾骨

D.髋骨与尾骨

E.耻、坐骨与骶骨

A公司是一个商业企业。由于目前的收账政策过于严厉，不利于扩大销售，且收账费用较高，该公司正在研究修改现行的收账政策。现有甲和乙两个放宽收账政策的备选方案，有关数据如下：

项　目	现行收 账政策	甲方案	乙方案
年销售额(万元/年)	2400	2600	2700
收账费用(万元/年)	40	20	10
所有账户的平均收账期	2个月	3个月	4个月
所有账户的坏账损失率	2%	2.5%	3%

已知A公司的变动成本率为80%，应收账款投资要求的最低报酬率为15%。坏账损失率是指预计年度坏账损失和销售额的百分比。假设不考虑所得税的影响。
要求：通过计算分析回答，应否改变现行的收账政策如果要改变，应选择甲方案还是乙方案

Observe that for the programmer，as for the chef,the urgency of the patron(顾客) may govern the scheduled completion of the task，but it cannot govern the actual completion．An omelette(煎鸡蛋)，promised in two minutes，may appear to be progressing nicely．But when it has not set in two minutes，the customer has two choices—waits or eats it raw．Software customers have had (71) choices． Now I do not think software (72) have less inherent courage and firmness than chefs，nor than other engineering managers．But false (73) to match the patron’s desired date is much more common in our discipline than elsewhere in engineering．It is very (74) to make a vigorous，plausible，and job risking defense of an estimate that is derived by no quantitative method，supported by little data，and certified chiefly by the hunches of the managers． Clearly two solutions are needed．We need to develop and publicize productivity figures，bug-incidence figures，estimating rules，and so on．The whole profession can only profit from (75) such data．Until estimating is on a sounder basis，individual managers will need to stiffen their backbones and defend their estimates with the assurance that their poor hunches are better than wish derived estimates．

A．tasks

B．jobs

C．works

D．scheduling

世界卫生组织确定的根龋诊断标准是（）

A.牙釉质上的白斑、着色的不平坦区

B.底部发软的病损、釉质潜在损害或沟壁软化者

C.CPI探针在根面探及软的或皮革样损害

D.中到重度氟牙症所造成的牙釉质上硬的凹陷

E.探诊时疼痛的龋损

区分犯罪预备和犯罪未遂的基本标志是( )。

A．犯罪分子是否已经完成犯罪预备行为

B．犯罪分子是否已经接近作案目标

C．犯罪分子是否已经着手实行犯罪

D．犯罪分子是否已经进入作案现场