这是我们学校给的答复: The federal government has not explicitly forbidden unpaid employment during the STEM OPT extension. However, you’ll note that in Section 8.7 on page 29 states student pursing the STEM extension must “work in a paid position for an E-Verify employer at least 20 hours per week.” http://www.ice.gov/doclib/sevis/pdf/opt_policy_guidance_042010.pdf We interpret this to mean that students cannot perform unpaid or volunteer work to satisfy the 20 hour per week employment requirement on the STEM OPT extension. 所以我们学校要求是必须是paid job。但似乎各个学校规定不一样,而且本身审查就不 严格,所以很多人用unpaid都申请到了extension。至于对以后的影响就不清楚了