磁铁矿石的条痕为（）。A、黑色B、绿色C、褐色D、红色

半通行地沟的断面尺寸是依据运行人员能弯腰走路，能进行一般的维修工作的要求定出的。一般半通行地沟的净高为( )。

A．1.2m

B．1.4m

C．1.6m

D．1.8m

根据《税收征收管理法》的规定，纳税人逃避、拒绝、阻挠税务机关检查时，税务机关有权采取的措施是() 。

A．责令改正并可处以罚款

B．查封账簿

C．冻结纳税人在银行的存款

D．移送司法机关

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．

（74）处填（）。

A．easy

B．difficult

C．simple

D．painless

为了比较水和煤油的吸热能力，小王做了如图的实验，在2个相同的烧杯中分别装有质量、初温都相同的水和煤油，用两个相同的酒精灯对其加热，并用相同的两支温度计分别同时测量水和煤油的温度变化，实验数据如下：

（1）在此实验中，为比较水和煤油吸热能力的大小，我们可以加热相同的时间，观察         的不同；也可以                               。

（2）分析下表中的实验数据可知：质量相同的水和煤油，                                                   

升高相同的温度时，    吸热的热量多，表明      的吸热能力大。     

液体	质量（g）	初温（℃）	末温（℃）	加热时间（min）
水	300	20	30	12
煤油	300	20	30	6

（3）由于物体吸收热量的多少不使用仪器测量，本实验中把吸收热量的多少转换成加热时间的长短，在探究活动中常用到这种方法。请你运用同样方法设计一个方案来比较电磁铁磁性的强弱                     

临床的标本（“未知疾病标本”）无法判断其危险程度，因此，每个临床实验室每天都面临生物安全隐患。