Răspuns:
1. "a paper" - generally, means that any paper works
"the paper" - a specific paper
2. "has grey hair" - her whole hair is grey
"has a grey hair" - only a piece of her hair is grey
3. "twenty students in the class" - twenty are supposed to be in the class
"only ten are in the class" - ten are present
4. "modern architecture" - futuristic architecture
"1970s architecture" - old architecture
5. aici nu inteleg prima propozitie, mi se pare incorecta
"to the sea" - he went to the water
6. "glass of milk and a cheese sandwich" - here the milk is an item and the cheese is used to make the other item, the sandwich
"cheese is made from milk" - here milk is used to create the item called cheese.