While "lengthen" is a verb, "long" describes something that is of great length.
For example:
* Verb: The road was lengthened to accommodate the growing traffic.
* Adjective: The road is now long enough to handle all the traffic.
While "lengthen" is a verb, "long" describes something that is of great length.
For example:
* Verb: The road was lengthened to accommodate the growing traffic.
* Adjective: The road is now long enough to handle all the traffic.