american-englishbritish-englishdifferencesnouns
When I watched the "American Album" program, Susan and Henry talked about New York, and she used the word 'subway'.
When I listened to BBC's '6 minutes English', I heard 'tube' used in the conversation.
And as I know, there is another word, 'metro', also used sometimes.
Could you please give me some more description about these words?
A rock is bigger, possibly immovable, you couldn't throw it with one hand, at a pinch you might be able to with two.
Above, a Google Image result for "Rock", below, for "Stone"
Note that a boulder is probably bigger than a rock1.
Below, a boulder
Oh, also note that rocks and boulders are made from stone.
(This answer is mildly tongue in cheek)
1 Notable exception: Uluru/Ayre's Rock.
In common usage, imbalance is the noun meaning the state of being not balanced, while unbalance is the verb meaning to cause the loss of balance. In the context stated, the noun form should be used.
Best Answer
Each city’s metro system has a “common name” that developed historically.
etc.