English - speaking people say many"thank you"every day. Early in the morning when a teacher  asks a student,"Good morning. How are you?",  his answer should be."I'm fine, thank you. And you?" This is the first "thank you" of a day. When you hear "Your skirt is nice." you say"Thank you. I'm happy you like it." At your birthday party, When people give you something and say"This is for you. Happy birthday!",you also answer, "Thank you." When your friend helps you clean the classroom after school, you say"thank you"  to him. When you hear people say to you "Your English is very good." , how do you answer it? You don't say "thank you" when  _  .
you hear someone say to you,"Your English is very good!" someone gives you a present you meet an old friend of yours you hear people say "good luck" to you