对于QBC型单杠杆气动差压变送器测量管上的三个阀（截止阀、平衡_爱下问搜题

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问题单项选择题

对于QBC型单杠杆气动差压变送器测量管上的三个阀（截止阀、平衡阀和冲洗阀），接入信号时应（）

A.先开截止阀，后开平衡阀

B.先开平衡阀，后开截止阀

C.先开平衡阀，后开冲洗阀

D.先开冲洗阀，后开平衡阀

答案

参考答案：C

阅读理解

During winter holiday,Wei Ming with his family would like to travel to another country, Before that, he surfed the Internet for some information.

Come to Austria
Soll is a village in the mountains in western Austria. And the Post Hotel is clean
and inexpensive. It is opened by a local family. From the hotel you can see the whole village, the forests and the mountains. Temperatures in winter are usually5℃ to 15℃ in the daytime, but much cooler by evening.

Enjoy Thailand!
When you visit Bangkok in Thailand, don’t miss the early morning river boat
trip to the Floating(漂浮) Market just outside the city. There you will find many kinds of fruits and vegetables. And you can pay for them when you sit in your boat. Don’t forget your hat: the sun can be strong and it may be as hot as 30℃ at noon.

Visit Hawaii!
Maybe the most beautiful place in Hawaii is Kauai. You can visit its long, sandy beaches in the south and west of the island, and mountains and forests in the north, but don’t be surprised if
it rains in the centre of the island. Daytime temperatures there are usually around 24℃ to 26
℃by the sea, and only a little cooler by late evening.

小题1:The advertisements above are about _______.

小题2:If you go to Bangkok,you can __________.

A．climb mountains

B．enjoy the scenery of forests

C．live in the Post Hotel

D．buy fruits while sitting in your boat.

小题3:According to the advertisements,we know that______.

A．the hottest travel place is Soll

B．maybe it often rains in the centre of Kauai’

C．the Floating Market is in the middle of Bangkok.

D．the Post Hotel in Austria is clean but the price is high.

填空题

氢氧化钠能有效地消除水中的碳酸盐硬度和镁硬度，其反应式如下：Ca（HCO₃）₂＋2NaOH—→CaCO₃↓＋Na₂CO₃＋2H₂OMg（HCO₃）₂＋4NaOH—→Mg（OH）₂↓＋2Na₂CO₃＋2H₂OMgSO₄＋2NaOH—→Mg（OH）₂↓＋Na₂SO₄MgCl₂＋2NaOH—→Mg（OH）₂↓＋2NaC从上述反应可以看出，只有（）硬度才消耗碱剂，而（）硬度和氢氧化钠作用后，除生成（）沉淀外，还同时生成了等物质的量的（）。