4 years ago I applied toursit visa to us and they rejected and said that you have not shownevidence

4 years ago I applied toursit visa to us and they rejected and said that you have not shown that you have sufficiently strong family,social,or economic ties outside the US. such ties can inculde employment, professional, educational family or social links,
Again I have applied a toursit visa and on the application form ask you
Have ever been refused a US visa, you can select YES or NO I selected YES
But he will ask you Explain.
my qustion is that how to explain please advice me thnx