回複：did not use joint tax return,

if your wife's income meets the requirement, no need to include your income as total houshold income and you don't need to complete I-864A. If your wife's income is not enough and wants to include your income, you must be lised in her most recent tax return and you have lived together for 6 months. If you do not meet this criteria and your wife's income is insufficient, you need joint sponsor. However, there is no harm to bring a job letter from your employer at the time of interview.