水的质量流量为30t/h，温度为90℃，如管道内的平均流速为4.4m/s，则管道的内径为（）mm

层流时，管内平均流速是最大流速的___倍（） 湍流时，管内平均流速约是最大流速的___倍（） It’s suggested that some activities to celebrate the 30th anniversary of the Reform and Opening-up. What advantages do you think London ________other cities in hosting the 30th Olympic Games? The 30th Olympic Games, ______ between July 27 and August 12 in 2012, will take place in London[ ] It was July 24th when he arrived in London, ______ the 30th Olympic Games would be declared open 3 days later. Lucy was born ______ January 30th, 1998, when her sister got married ______ a fashion designer. How long will it be ________ the 30th Olympic Games is held in London? —It won’t be two years, I think The 30th Olympic Games, _______ between July 27 and August 12 in 2012, will take place in London. The moment the people of London heard that their city had won the bid for the 30th Olympic Games, they ________ cheers. On May 30th, 2005, one bowl in the Ming dynasty(朝代)________at the price of 30.36 million Hongkong dollars. （）According to the terms of the contract, the shipment is to be effected by 20 July and we have the B/L by the 30th at the latest. The 30th Olympic Games, officially_________as”London 2012 Olympic Games”, will take placefrom July 27 to August 12 [ ] 按《JGJ/T132-2009居住建筑节能检测标准》要求，在检测室内平均温度时，室内平均温度检测数据记录时间间隔不宜超过30min（） 在检测室内平均温度时，室内平均温度检测数据记录时间间隔满足要求的是（） I spent _______ awful holiday this summer because _______ big flood on July 30th made lots of people lose lives. 在检测室内平均温度时，下面室内平均温度的检测持续时间不正确的是（） 流量与流速的关系：V=uA，G=（）。其中V为体积流量，u为流速，A为管道的截面积，G为质量流量，ρ为流体密度。 流量与流速的关系：V=uA，G=（）。其中V为体积流量，u为流速，A为管道的截面积，G为质量流量，ρ为流体密度 某管中流体流动速度为1.2米/秒，如流量加倍，管道中流速为（）