简述液化石油气真空泵原理。

China's government has issued a severe weather warning after the heaviest snowfalls in decades. The country is experiencing transport delays and power cuts as millions of people prepare to make long journeys home for the Chinese New Year. This report from Quentin Summerville: China hasn't experienced weather this bad in decades. And as the country prepares for Chinese New Year, the disruption couldn't come at a worse time. Over 100,000 people are stranded(搁浅) in Guangzhou railway station in the south. It may climb to as many as 600,000 as more people arrive to make their journeys home for the Spring Festival. Travellers have been evacuated to nearby sports stadiums and exhibition centres.

Across China around nineteen airports have shut because of the weather. Around half the provinces in the country have had to start rationing power(定量供电), according to the state media. The government has suspended（暂停） coal exports in favour of home consumption. At least a dozen people died over the weekend because of heavy rains and the snowfall.

The Spring Festival is China's most important holiday when people journey home to be with their families. For millions of the country's migrant workers it's their only holiday. Some two billion journeys were made during the festival last year, making it the largest migration of people on the planet. And even without the severe weather, conditions on overcrowded trains and buses are terrible. The holiday stretches China's transport system to its very limits

小题1:Choose the best title for this passage.

A．Heavy snow hits China

B．Chinese New Year in snow

C．China’s terrible translation system.

D．An accident小题2:Which is not true according to the passage?

A．The heavy snow is the worst disaster in decades in China.

B．No other cities in the world have more travellers in festivals than in China.

C．The government doesn’t care for people’s life in disaster areas.

D．The country’s migrant workers have more than one holidays to celebrate, according to the passage

元杂剧音乐体系最为明显的特征是（）。

t检验法适用于（）的两组数据的比较检验。

A.样本容量较少、总体方差未知但要不同精度

B.样本容量较大、总体方差未知但要等精度

C.样本容量较少、总体方差已知但要等精度

D.样本容量较少、总体方差未知但要等精度

从资产负债表来看，可能导致流动资产增加的因素包括（）。

A.固定资产重置

B.季节性销售增长

C.长期投资

D.长期销售增长

E.提供的商业信用减少

为各个制剂制定，为配制该制剂的标准操作，包括投料、配制工艺、成品包装等内容称为（）

A.标准操作规程

B.配制规程

C.物料

D.洁净室

E.一般区