3 sentences

1. 他从小就励志要报效国家。

   tā cóng xiǎo jiù lì​zhì yào bào​xiào guó​jiā.

   He has been determined to serve his country since he was a child.

   Source: Dong Chinese Dictionary

2. 我们要努力学习，以报效祖国。

   wǒ​men yào nǔ​lì xué​xí, yǐ bào​xiào zǔ​guó.

   We must study hard in order to serve our country.

   Source: Dong Chinese Dictionary

3. 他从小就立志长大后要参军报效国家。

   tā cóng xiǎo jiù lì​zhì zhǎng​dà hòu yào cān​jūn bào​xiào guó​jiā.

   Since he was a child, he has been determined to join the army and serve his country when he grows up.

   Source: Dong Chinese Dictionary