until or unless after 2030

terrytan

Member
Chinese
Hello everyone,
Following sentence comes from a grammar test. Can I use unless to replace the underlined word until? Do they mean the same thing? Thanks!
Most experts agree that we are not going to have true driverless cars on our roads until after 2030.
 
  • Glasguensis

    Signal Modulation
    English - Scotland
    Until is used when we want to indicate that something can or will change after a period of time or when something evolves after a period of time
    I will watch television until 5PM
    Keep stirring until the mixture is smooth

    Unless is used to indicate that something can or cannot currently occur, but that this could be inversed if some condition is met.
    I will go cycling tomorrow unless it rains
    You can’t get in unless you’re on the list

    In your example it is clearly a period of time which is in play, so only until fits.
     
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