1. Clay tablets were very heavy . 2. Clay tablets were very when they were dry. 3. Clay tablets were soft hard

Solution:

• 1. Clay tablets were very hard. (Clay tablets are known for their durability and hardness, especially when fired or dried.)
• 2. Clay tablets were very durable. (The context implies longevity and reusability, suggesting durability.)
• 3. Clay tablets were used for writing. (Historical context indicates clay tablets were primarily used for writing cuneiform and other scripts.)

Answer: 1. hard, 2. durable, 3. used for writing