Question

1. Year, length, foot (measurement of length) - what kind of nouns(Proper, Common, Abstract) ?

2. Knock at the door, but knock _ the window. (What preposition should be in the gap).

Debraj

Answer 1

1. common nouns

2. 'Knock at the door' means 'knocking sound near the door'; 'knock on the window' means 'someone is knocking on the surface of the window'.