• The only person he thought about was himself.
• The earth‘s atmosphere is made up of a mixture of highly mobile gases.
• Winters in Prague, the capital city of the Czech Republic, can be bitterly cold.
• The President made a brief statement to the press.
• The sun is the generator and maintainer of all life.

a, an or the is not used with Breakfast, lunch, dinner . but if there is an adjective before, a, an or the is used.

• We have breakfast at 8.
• I usually have lunch at home.
• They have just had dinner.
• What shall we cook for dinner?
• I insist you stay for dinner.
• Why don’t we go on our discussion after lunch?
• 
  

BUT:

• The chefs prepared a magnificent dinner for the Queen and her guests.
• A traditional Japanese breakfast typically consists of rice, miso soup and pickled vegetables.
• We had a large breakfast.
• We only had time to grab a quick lunch.