谢谢８老师！请问８老师

１）如果旧公司的绿卡排期到了，是否不能用旧公司的I－１４０做H１B延期了？

-Yes, he/she can. But it only can be
extended for one year if the petition is filed when the PD is current. However,
the H-1 extension application can be filed in advance up to 180 days before the
current H-1 expires, so if possible, your friend may ask the employer to file
the H-1 earlier before the PD is current so that the H-1 can be extended for
another 3 years.
 

那么请问８老师，如果新公司不给办绿卡，H１B延期只能延１年，最多允许延几次呢？能不断地延下去吗？
谢谢８老师！