Looking on the internet deeply has found these results:

I must learn my duties is the most popular phrase on the web.

I must know my duties 11 results on the web	I must learn my duties 12 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
to you, to the Emperor, and to my country. I know my duty as an Adams. Father, I know my duty. I know my duty I know my duty, sir. I know my duty, Captain. Stand aside, I know my duty. I know my duties a believer.	I must learn to work first. Every citizen has a duty to learn of this that threatens his home... his children. If port authorities, when exercising their normal duties, learn that a ship within their port has Starting tomorrow, I must learn how to control myself. I must learn why he was suddenly dismissed. The Commission has a duty to learn the lessons of the storm disaster, and strengthen the effectiveness of Community texts. Learn the first duty of ninja. Every citizen has a duty to learn of this that threatens his home... ...his children.

I must know my duties

11 results on the web

I must learn my duties

12 results on the web

More popular!

I must learn to work first.
Every citizen has a duty to learn of this that threatens his home... his children.
If port authorities, when exercising their normal duties, learn that a ship within their port has
Starting tomorrow, I must learn how to control myself.
I must learn why he was suddenly dismissed.
The Commission has a duty to learn the lessons of the storm disaster, and strengthen the effectiveness of Community texts.
Learn the first duty of ninja.
Every citizen has a duty to learn of this that threatens his home... ...his children.