since 用咩tense?

Present prefect!!!!!!
例如: has sung (單人 +has +participal) , have eaten (雙人或以上
+have +participal)

It's a good idea if you use the word 'since' with simple future tense.
圖片參考：http://tw.yimg.com/i/tw/ugc/rte/smiley_14.gif

since should 用 present perfect tenses

Present perfect tense or past perfect tense
表示從過去某時以來
e.g. I have lived in Mong Kok since 2003.

since 用 現在完成式 即 present perfect tense 見到 yet,since,already,just,for,before,never 用 現在完成式 e.g. I have worked for this school since 1982. 現在完成式點用? I we you they 用 have + p.p.(present perfect) he she it用 has + p.p. e.g. She has gone to airport. You know?