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对(),国家标准《点燃式发动机汽车排气污染物排放限值及测量方法(双怠速法及简易工况法)》(GB18285—2005)规定,要进行过量空气系数(λ)的测定。
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水平转动(1G)&159mm×8mm管子对接采用钨极氩弧焊时,背面焊缝余高应不大于()。
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气相爆炸分为哪几类?
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矿井反风后,总回风流中,一翼回风流或主要回风道风流中的瓦斯浓度都不得超过()。
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地形图比例尺常用分子为1的分数形式表示,则( )。
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ULTRASITE基站4+3(2个扇区),需要()块基带单元设备BB2F。
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红丹粉颗粒很细,用时少量()油调和均匀。
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多级离心泵平衡管或平衡盘作用是什么?
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Every country has traffic rules and signs, but are they the same? In most countries, there are street and road signs with 21________ about location,directions,dangers,cautions, and rules of the road. These 22 _________ tell drivers and pedestrians what to do and what not to do,including speed and parking 23 ________,places to stop,when to make turns,and other 24________.However, specific local traffic laws and practices usually differ around the world. For instance, in Japan, Indonesia, South Africa, the United Kingdom, and other countries ,steering 25________are on the right side of vehicles ,and cars and trucks drive on the left side of the road. In other 26 _________,such as the United States,Saudi Arabia,Italy, and Mexico,steering wheels are on the left side of vehicles ,and cars and trucks 27________on the right side of the road. An illustration of a local 28________law is the regulations for pedestrian and school 29 ________ in some Mexican cities:drivers rarely respect the rules,so for safety, people cross streets only at stop lights, on roads with little traffic, or on pedestrian-only 30 _________ across wide avenues.
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抑郁发作时的躯体症状群包括()