Ответ:
- Many people talk but few have something to say.
- You need a few potatoes to make some pancakes.
- A little porridge is enough for my breakfast.
- This lemon drink is sour. Put a few lumps of sugar in it.
Обоснование: few / a few используются с исчисляемыми существительными во множественном числе, а little / a little — с неисчисляемыми.
