I am so sad about this; as you know, in China, we have have been learning English for more than 10 years.
#I am so sad for this, as you know, in China, we have learned English more than 10 years ago.
#I am so sad for this, as you know, in China, we have learned English more than 10 years ago.
#I am so sad for this, as you know, in China, we have learned English more than 10 years ago.