1) it was (hard - hardly) for us to tell her the truth. 2) he (hard - hardly) ever comes to see us because he is always very busy.3) we could (hard - hardly) recognize the place: everything had changed so much.4) it was a (hard - hardly) day for everybody. 5) he spoke too fast and it was (hard - hardly) to understand him.6) he had (hard - hardly) any work to do. 7) she was so tired that she could (hard - hardly) stand.....8) how many (meal - food) a day do you have? 9) bring enough (meal - food) any water for the trip.10) in england lunch is usually the biggest (meal - food) of the day. 11) they talked a lot during the (meal - food).12) do they serve good (meal - food) in this restaurant?

Вот правильные варианты для ваших предложений с краткими пояснениями:

1. It was hard for us to tell her the truth.
   (Hard в значении «трудно/тяжело» выступает прилагательным к дополнению).
2. He hardly ever comes to see us because he is always very busy.
   (Hardly — наречие, означающее «едва ли» или «почти никогда»).
3. We could hardly recognize the place: everything had changed so much.
   (Hardly означает «с трудом/едва ли»).
4. It was a hard day for everybody.
   (Hard — прилагательное «трудный/тяжелый»).
5. He spoke too fast and it was hard to understand him.
   (Hard в значении «сложно»).
6. He had hardly any work to do.
   (Устойчивое выражение hardly any означает «почти никакой»).
7. She was so tired that she could hardly stand.
   (Hardly в значении «едва»).
8. How many meals a day do you have?
   (Meal — это прием пищи как событие (завтрак, обед), food — еда как субстанция. Здесь во множественном числе).
9. Bring enough food and water for the trip.
   (Food — еда в общем смысле как провизия).
10. In England lunch is usually the biggest meal of the day.
    (Речь идет о конкретном приеме пищи).
11. They talked a lot during the meal.
    (Имеется в виду процесс приема пищи).
12. Do they serve good food in this restaurant?
    (Речь о качестве самой еды/продуктов).

Если вам нужно разобрать грамматические правила употребления наречий или разницу между исчисляемыми и неисчисляемыми существительными, дайте знать.