1. 表未來狀況,條件句(即 when、if、unless、once、as soon as、until、after 等引導的副詞子句)使用現在式,主要子句則使用未來式(即 will + 原形動詞)。為方便記憶起見,讀者可牢記下列幾個字:
條現主未(條件句用現在式,主要子句用未來式)
例: When I will be free, I will help you with your report. (×)
When I am(現在式) free, I will help(未來式) you with your report. (○)
(我有空時會幫你寫報告。)If I will have time, I will call you. (×)
→ If I have(現在式) time, I will call(未來式) you. (○)
(我若有空就會打電話給你。)I won't help you unless you will take my advice. (×)
→ I won't help(未來式) you unless you take(現在式) my advice. (○)
(除非你接受我的建議,否則我不會幫助你。)
2. since 表『自從』的用法
since 可做副詞連接詞、介詞、或副詞,不論屬何種詞性,所修飾的動詞均使用現在完成式或現在完成進行式
a. 副詞連接詞(引導過去式子句)
例: Peter has studied English (ever) since he attended junior high school.
(自唸國中起,彼得就一直學英文。)b. 介詞(以時間名詞或動名詞作受詞)
例:
Peter has been studying English | (ever) since 2000. (ever) since ten years ago. (ever) since attending junior high school. |
(自二○○○年起/十年前/唸國中起,彼得就一直在學英文。)
c. 副詞:只用於下列句型
主詞 + 過去式動詞 + 過去時間 + and have / has since + 過去分詞
⋯⋯之後就一直⋯⋯例: John moved here two years ago and has since lived here.
(約翰兩年前搬到這裡,之後就一直住在這裡。)