現在就該準備了，有時候預約需要一兩個月時間

邀請信很簡單，寫明意思就行，比如

To whom it may concern,

I, xxx, would like to invite my parents, xxx and xxx, to visit me in April 2007 for a period no more than 6 months. All expenses including room, board and insurance are my sole responsibility.

I am currently an employee in XYZ Inc. My current status is H1B. Thank you for your favorable consideration!


Sincerely,

xxx