电液转换器（伺服阀）是由一个极化的电气力矩马达和两级的液动放大及机械反馈系统组成，第

中学生小明他的爸爸一起出去吃饭，他爸爸在喝了很多酒以后，还坚持要自己开车回家，小明进行了劝阻。你认为下列选项中哪些可以成为小明劝阻的正确理由：（   ）

①喝酒不开车，既是对自己负责，也是对他人、社会负责   

②酒后驾车是一种违法行为

③喝酒不喝酒是公民的自由

④酒后驾车危害公共安全

A．②③④

B．①②④

C．①③④

D．①②③

下面各式计算结果为-7x-5x²+6x³的是  [ ]

A．3x-（5x²+6x³-10x）

B．3x-（5x²+6x³+10x）

C．3x-（5x²-6x³+10x）

D．3x-（5x²-6x³-10x）

No one knows yet the accurate number of lives which have been lost in this terrible fire .But reports suggest that it is more than one hundred .

A wall of flames fifty feet high and at least one hundred and fifty miles wide is now racing towards the forests and rich farmlands of southern Victoria . Towns less than one hundred miles from Melbourne will be in danger unless the wind changes . People are rushing excitedly into the streets . The police have warned them not to see the fire but many people are doing so .

The cause of the fire is unknown . No rain has fallen in this part of Australia for three months , and the hot , north-west wind from the great central desert is blowing at more than thirty miles an hour .

The firefighters are travelling to the fire by road , rail and air . But it is not easy to get there . Flames and fallen trees have cut off or blocked roads and railway lines . The thick smoke often prevents them from finding the air strips (飞机跑道).

It is said that the fire has brought the greater danger to the country since the Second World War .

小题1:By the time the article was written , the fire        .

A．had just broken out

B．had been put out

C．was spreading violently

D．was coming to an end小题2:The writer wrote this article mainly to tell people        .

A．the fire was terrible and dangerous

B．it was impossible to put out the fire

C．more than one hundred people died of the fire

D．to join in the fight against the fire小题3:In the 4th paragraph , the writer suggested that        .

A．the fire would soon be controlled by the firefighters

B．it would be very difficult to put out the fire

C．the government was paying great attention to the fire

D．the fire had caused great losses and the airport was in ganger小题4:The underlined word “ accurate” in the first sentence has the same meaning as        .

A．recent

B．whole

C．rough

D．exact

简述影响PIN光电二极管响应速度的主要因素。

焊接顺序和焊接方向不合理是引起（）变形的主要原因。