Complex sentence: It could have been recalled along the way, but no further diplomatic progress was made and on 1 December, Emperor Hirohito approved, in Imperial Conference, attacks against United States, Britain, and the Netherlands.
Split into simpler sentences: It could have been recalled along the way, but no further diplomatic progress was made. On 1 December, Emperor Hirohito approved, in Imperial Conference, attacks against United States, Britain, and the Netherlands.