As words are divided into different classes according to the work they do in sentences, it is clear that we cannot say to which part of speech a word belongs.
They arrived soon after. (Adverb)
They arrived after us. (Preposition)
They arrived after we had left. (Conjunction)
Name the part of speech in the following sentences
1. Still waters run deep.
2. He still lives in that house.
3. The up train is late.
4. He told us all about the battle.
5. Let us move on.
6. Suddenly one of the wheels came off.
7. Sit down and rest a while.
8. It weighs about a pound.
9. He was only a yard off me.
10. The after effects of the drug are bad.