Burner is not

关于Mg在Bunsen burner火中的反应
如果把一小条Mg放在Bunsen　burner火焰中,Mg会产生耀眼的白色光芒.Mg是和什么物质产生反应的?是Bunsen　burner里碳氢化合物（CH4）和氧产生的二氧化碳(CO2)还是氧气(O2)?

Hot air balloons have burners to keep the air hot.动词不定式做定语还是做目的、结果状语?

英语翻译
The burner control box should now be activated.if in a lockout situation,the reset button should be reset.
Please check the relevant control box,manufacturer's literature for the start up and run sequence of the control box.A separate data sheet is provided in the technical data section of this manul for the particular control box fitted.
check the rotation of the motor with a direct drive system burner,the correct rotation is anticlockwise looking onto the back end of the burner motor.for 3 phase motors,the isolator can be reversed by swapping over any two of the three wires on the incoming mains supply.the rotation of single phase motors will have been set at the factory.
the air pressure proving switch should be set to 1.5 mb initially.the final air pressure switch setting will be determined during the operation phase of the commissioning.

在一个propane burner上放两个rigid plastic tubes,一个直径大一个直径小,先把小的缓缓的放在火焰上,会听见爆炸声,为什么.接着把大的套在小的外面,移动大的时会有声音,为什么
实验2
在一个吸管上打几个眼,吹吸管时会有声音,为什么.套个大吸管在外面,吹小吸管同时移动动大吸管,会有不同的声音,为什么

fill up your burner with water and add only few drops of oil 求翻译

我怎么就理不顺这个句子?
The Bunsen Burner is so named because it is thought ______by Robert Bunsen.
A.to be invented B.having been invented
C.invented D.to have been invented

改错The Bunsen burner is so named because it is thought to be invented bu Robert Bunsen,who was Ger
The Bunsen burner is so named because it is thought to be invented bu Robert Bunsen,who was German by birth.

1.The bunsen Burner is so named that it is thought ( ) by
Robert Bunsen
A.to be invented B.to have been invented
选哪一个?为什么?
2.-Have you guaduated from collage?
-Yes,( )
A.I have been studying French for 4 years.
B.I studied French there for 4 years.
C.I have studied French for 4 years.
A,C有什么区别?过去时里可以有for?选哪一个?