SOURCE

"I? love ?? the ?great ? ?wall in ?beijing"
  .split("")
  .reduce((acc, cur, index) => {
    return cur == "?" || (cur == " " && acc[acc.length - 1] == " ")
      ? acc
      : [...acc, cur];
  }, [])
  .join("")
  .replace("g", "G")
  .replace("w", "W")
  .replace("b", "B");