Did you work as TA/RA at school? The tax is withheld by your employer from your paycheck. At the beginning of the next year, your employer sends a W2-form that summarize the tax withheld (federal/state/local/social security/ medicare....). During OPT, you probably do not have to pay social security and medicare if the tax treaty is still valid, meaning you did not work as TA/RA for over 5 years. You file tax return with 1040 before April 15 with uncle Sam and probably get some refund or pay more. Employees fall into two categories: Exempt (most full time direct hire positions) and Non-Exempt (contractors). Exempt employees are Not paid extra hour. Computer policy is dependent upon your employer, follow that like religion, or you'll be fired or even put to jail. Your employer should have dressing code policy.人字拖 looks disgusting to me and I've never seen anybody wear that or even sold in store. Where did you get it? You can find answers to most questions in your Employee Handbook or ask your HR.