Cho dạng thích hợp của từ trong ngoặc 1.I find History really ____________ (interest) 2. I hope you'll join in our Christmas __________ (celebrate) 3. I will __________ be back by ten(definite) 4. Vietnamese __________ have fewer vacations than American ones (study)

What does the doctor recommend to eat?

What do happy people do? 

What kind of food will help people to keep fit and stay healthy?