The modal verb may in the fragment of the text “It may be years before the economic benefits of natural gas vehicles can be realized” (lines 35-36) is associated with the idea of
The sentence of the text “But were production to increase significantly, economies of scale would bring prices down” (lines 28-29) has the same meaning as:
In the statement “As of 2009, Argentina had more than 1.8 million in operation and almost 2,000 natural gas filling stations” (lines 4-6), the expression as of means: