♠艾瑞克隨處溜躂．蒲公英隨心飄逸♠

雖然a和the都是加在名詞前的冠詞，但兩者間有什麼不同？
         
a/an→．只能接單數名詞
　　　．沒有特定的指某一個東西

the→．可接單數或複數名詞
          ．明確指出是哪一個

EXAMPLE→[a/an] There is a man standing over there.
                  →[the] The blue car outside is mine.



ago VS. since

ago→某事在過去某個時間點發生過
[用法]→一段時間 + ago
since→某事在過去發生，並且持續進行到現在
[用法]→since + 子句(S. + V.)
              since + 特定時間點

EXAMPLE→[ago] She began working there seven years ago.
                  →[since] She has worked there since 1999.