這樣英文正確嗎？還是應是應怎樣更改thanks ,你什麼時候有空我們約會？When do you have time we can go a date?

When do you have time to go on a date?

To go on a date.才是正確的"英語語句"，就算原用你的寫法"...we can go "on" a date"也是可以的，不過會較累贅(因為難道你約她不是"你們"嗎)。

When you have time we can hang out together.
這樣比較好,口語的話.......

what time can you go a date with me ?
較簡單 !
Dialog:

Boy; what time can you go a date with me ?
girl: what ?
Boy; a date !
girl: welcome to hear that, when ?. Ok it's any time I can.[ 肯定 ]
girl: nice to here that, but I have something to do, I can't. [否定 ]