在一个长50cm,宽30cm,高10cm的长方体石块中间凿出一个棱长10cm的正

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问题:

在一个长50cm,宽30cm,高10cm的长方体石块中间凿出一个棱长10cm的正方体后,这个石块的表面积是多少?

考点:长方体的表面积正方体的表面积
题型:解答题

关于导水机构水力损失,说法正确的是:()。

A、导水机构的水力损失与工作水头、过流量、导叶数及过流表面粗糙度成正比,与导叶相对高度平方成正比;

B、导水机构的水力损失与工作水头、过流量、导叶数及过流表面粗糙度成正比,与导叶相对高度平方成反比;

C、导水机构的水力损失与工作水头、过流量、导叶数及过流表面粗糙度成反比,与导叶相对高度平方成反比;

D、导水机构的水力损失与工作水头、过流量、导叶数及过流表面粗糙度成反比,与导叶相对高度平方成正比;

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为预防输血后肝炎的传播,错误的叙述是()

A.提倡义务献血

B.提高筛选献血者的血清学检测试验的灵敏度

C.加强对血液制品的肝炎病毒灭活效果

D.严格消毒制度,提倡使用一次性输血器

E.应用抗HCV筛选可排除所有具有HCV传播的献血者

题型:解答题

慢性菌痢的临床类型有()

A.慢性隐匿型

B.慢性混合型

C.慢性迁延性型

D.慢性普通型

E.急性发作型

题型:解答题

Melissa and LoveLetter made use of the trust that exists between friends or colleagues. Imagine receiving an (16) from a friend who asks you to open it. This is what happens with Melissa and several other similar email (17) . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages (18) .

A. virtual B. virus C. wormsD. bacteria

As administrators seek to block dangerous email attachments through the recognition of well-known (19) , virus writers use other extensions to circumvent such protection. Executable (.exe) files are renamed to .bat and .cmd plus a whole list of other extensions and will still run and successfully infect target users.
Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which, while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the (20) access to your network.

题型:解答题

应急计划内容包括()等。

A.报警联络步骤

B.应急措施

C.可能事故的性质和后果

D.应急指挥中心地点和机构

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