input: Write a function to generate a list of lists of words from the given list of strings, where each sublist starts with the first word of its corresponding string followed by the subsequent words.
  assert get_word_lists(["Hello world", "This is a test"])==[["Hello", "world"], ["This", "is", "a", "test"]]
output: def get_word_lists(strings):
      return [[word for word in string.split()] for string in strings]