关于准确度与精密度的关系，描述不正确的是（）。 A.精密度高，准确度也高 B.精

患者，女性24岁，因膝关节疼痛及轻度活动受限1个月入院，主诉低热、盗汗、纳差及体重减轻，查体：T37.4℃，P86次／分，R20次／分，BP120/80mmHg，膝关节呈梭形肿胀，局部压痛，皮温升高，周围肌肉萎缩，有关节积液，关节呈屈曲畸形，关节半脱位，试验室检查：ECR增快，X线表现不明显，磨砂玻样改变，可见死骨空洞。

如该患者拟行病灶清除术，下列哪项是禁忌症（）。

A.有混合性感染，中毒症状明显者

B.窦道流脓经久不愈者

C.骨髓腔内有积液者

D.伴有肺结核活动期者

E.脊柱结核有脊髓受压表现者

F.伴有大脓肿者

凹陷状痕迹的凸凹象与形成痕迹的工具的凸凹象相反（）。

A、错误

B、正确

C、不完整

D、正确、完善

下列说法中正确的是（）。

A.人耳对1000~4000赫兹的声波最敏感

B.人耳对16~20000赫兹的声波最敏感

C.老年人首先丧失的是对高频声波的听觉

D.老年人首先丧失的是对低频声波的听觉

我国政府采购的主体是

A．国家机关

B．事业单位

C．国家机关、事业单位和社会团体

D．国家机关、事业单位、社会团体和国有企业

It’s all annual back-to-school routine. One morning you wave goodbye, and that (1) evening you’re burning the late-night oil in sympathy. In the race to improve educational standards, (2) are throwing the books at kids. (3) elementary school students are complaining of homework (4) What’s a well-meaning parent to do.As hard as (5) may he, sit back and chill, experts advise. Though you’ve got to get them to do it, (6) helping too much, or even examining (7) too carefully, you may keep them (8) doing it by themselves. "I wouldn’t advise a parent to check every (9) assignment," says psychologist John Rosemond, author of Ending the Tough Homework. "There’s a (10) of appreciation for trial and error. Let your children (11) the grade they deserve. " Many experts believe parents should gently look over the work of younger children and ask them to rethink their (12) . But "you don’t want them to feel it has to be (13) ," she says.

That’s not to say parents should (14) homework-first, they should monitor how much homework their kids (15) . Thirty minutes a day in the early elementary years and an hour in (16) four, five, and six is standard, says Rosemond. For junior-high students it should be " (17) more than an hour and a half," and two for high school students. If your child (18) has more homework than this, you may want to check (19) other parents and then talk to the teacher about (20) assignments.

20（）

A.finishing

B.lowering

C.reducing

D.declining