a tray of food的用法和样例：
- She came in with a tray of drinks.
- She brought me a tray of tea and sandwiches.
- A servant came by with a tray of bottles.
- The trouble with having a big dog like an Alsatian in a small flat is that it always seems to be in the road when you are carrying a tray of glasses.
- After another three hours, the snail returned with a tray full of food.