機器
and the economy
background and sky
beautiful
blue
china
colorful
construction
control
diesel oil
energy
enterprises
equipment
exploration
extraction
features
fuel
gasoline
ground
industry
internal
iron and steel
labor
money
oil
oil fields
pipe
power
pressure gauge
process
production
professional
raw
shut down
store
strength
switch
technology
tubing
turning
valve
wealth
well run
work