2.( 1) Do your best: Do your best.

(2) Kneeling and surrendering: Kneeling and begging for mercy is a metaphor for surrender.

3.

(1) Never forget to serve your country;

(2) Advocating that the Northern Expedition should be recalled to China;

(3) visiting the front line many times;

(4) Never forget national unity.

The answer is not unique, just right.