Question

alongside
along·side
I
 /əˈlɑːŋˈsaıd/  adv  
  : along or close at the side
   We waited for the other boat to come alongside.
  alongside of
    chiefly US    informal   : next to or together with (someone or something) : alongside
    The police car pulled up alongside of our car.
    children working alongside of their parents
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II
  prep  
  1 : next to (someone or something)
   The children work alongside their parents in the field.
  2 : along the side of (something)
   Bring the boat alongside the dock.
  3 : at the same time as (something) : together with (something)
   one theory taught alongside the other
   The town grew up alongside the college.