Based on the context and the partially given sentences, here are the suitable words to fill in the blanks:

**Paragraph 1:**
3. filtered
4. harden
5. rolled
6. chemicals
7. processed
8. products

Complete steps:
After the latex has been (3) filtered and the dirt removed, it is poured into large tanks and left to (4) harden. When the latex is hardened, it is dried and sent to factories. At the factories, the rubber is (5) rolled into thin sheets and special (6) chemicals are added to it. The sheets of rubber are (7) processed and sent to other factories which manufacture rubber (8) products.

**Paragraph 2:**
1. of
2. sugar
3. example
4. increased
5. eat
6. ago
7. looked
8. out

Complete steps:
Since the beginning of this century, tooth decay has greatly increased. The amount (1) of sugar in our food has also increased. Doctors and dentists now know that (2) sugar is the chief cause of tooth decay. Eskimos' teeth, for (3) example, started to (4) decay when they began to (5) eat sweeter food. Long (6) ago, doctors did not like to treat people's teeth. Barbers and blacksmiths (7) looked after people's teeth and pulled them (8) out when they decayed. Some people thought the toothache was a punishment from gods.

**Section IX:**
1. This machine has not been used for years.
2. My bicycle is not as expensive as yours.
3. He’s not tall enough to play basketball.
4. No knowing what to buy, she asked her mother.

These words and complete sentences should fit well in the specified blanks and fulfill the requirements of the assignment.