used in negative statement to describe a situation that has existed up to this point or up to the present time; "So far he hasn't called"; "the sun isn't up yet"
used after a superlative; "this is the best so far"; "the largest drug bust yet"
move downward and lower, but not necessarily all the way; "The temperature is going down"; "The barometer is falling"; "The curtain fell on the diva"; "Her hand went up and then fell again"