英文!!!!!!!!!!!!!!!!!!!

1. cleanness - clean - clean- clean
- clean as adv., e.g., I clean forgot about it. (= I fogot about it completely) No need to put -ly. But usually used in informal way.
2. depth - deepen - deep- deeply
3. safety - save - safe - safely
4. attendance - attend - attendant - attendantly
5. hardness / hardship - harden - hard - hard/hardly
- hard can be used as an adv. e.g., Work hard.
6. addition - add - additional - additionally
7. Sharpness - sharpen - sharp - sharply / sharp
- sharp can be used as an adv. e.g., The lecture started at 3 o'clock sharp.
8. weakness - weaken - weak - weakly
9. strength - strengthen - strong - strongly
10. what is the question?
11. death - die - dead - dead / deadly
- dead is an adv. and is frequently used. e.g., He is dead against the idea (He is absolutely against the idea). Deadly is an adv., but not often used. The word is usually used as an adj, e.g., A deadly disease.
12. success - succeed - successful - successfulness

A good exercise!