哥哥拿到了B2簽證，一年有效，多次往返。可有個問題：這種B2簽證是否有要求必須在某年某月某日前必須入境？
-Yes, there is a Expriation Date on the visa. Your brother has to enter US before the expiration date.
我看了簽證，沒有看到要求，隻有一個"control number",
-This is for USCIS/CBP to use to track the visa. Control Number is not the visa number. Visa number is the one with red color.
不知什麽意思。請哪位指點一下，先謝謝了。
