英语句子翻译，高手请进

1.他独自一人完成了这项被认为是不可能的任务（by himself）

2.当他长大后，他开始从事写作并以此作为终身事业（take up）

1. He finished the task by himself which was thought to be impossible.

2. After he grew up, he took up writing as his whole-life career.

1、He alone is considered completed this impossible task.

2、When he grew up, he started writing and as a lifelong career.

1 He finished the mission impossible by himself

2 When he grew up ,  he took up writing and took it as his life-long career