低钾血症时肠鸣音的变化是（）。 A.肠鸣音正常 B.肠鸣音活跃 C.肠鸣音亢进 D.

有下列物质：①空气②水③氧气④高锰酸钾⑤铁粉⑥矿泉水⑦过氧化氢⑧高锰酸钾制氧气后的剩余物（用序号填空），试回答：    

属于混合物的是____，属于纯净物的是____，属于化合物的是____，属于单质的是                    。

促进去甲肾上腺素释放（）

A.多巴胺

B.麻黄碱

C.两者均是

D.两者均否

陆生植物的叶片、花瓣和果实表皮常常发生角质化。

In the following essay, each blank has four choices. Choose the most suitable one from the four choices and write down in the answer sheet.

The key to SNMP (71) is its simplicity. It has a small command set that does a good job of collecting information from (72) any network device. In a SNMP environment, (73) of the work is handled by the network management system. Devices that are being managed are not (74) with processing (75) that might affect their performance.

75（）

A．time

B．power

C．speed

D．overhead

热轴预报主要内容是什么？