Here's how it works:
* Propelled: This is the past participle of the verb "propel," which means to push or drive forward.
* Themselves: This is a reflexive pronoun, meaning that the action is done by the subject of the sentence to itself.
Examples:
* The rockets propelled themselves into space. (The rockets used their engines to move themselves forward.)
* The fish propelled themselves through the water with their tails. (The fish used their tails to move themselves forward.)
* The athletes propelled themselves over the hurdles. (The athletes used their strength and momentum to move themselves over the hurdles.)
To understand what something propelled itself, you need to know how it generated the force to move forward. For example:
* Rockets: Use engines that burn fuel to create thrust.
* Fish: Use their tails to push against the water.
* Athletes: Use their muscles to create momentum.
Let me know if you have any other questions!