Question

Complete this sentence with passive or active verbs as necessary. Writing is a very early human achievement. As far as we know, the earliest writing systems (develop) approximately 6000 years ago.

Answer 1

developed

Step-by-step explanation:

Writing is a very early human achievement. As far as we know, the earliest writing systems developed approximately 6000 years ago.

past tense of develop is developed.

Answer 2

Writing is a very early human achievement. As far as we know, the earliest writing systems was developed (passive form of verb) approximately 6000 years ago.