Q: by和until有什麼區別?
1. by表示在某特定的時間之前或不遲於某特定的時間,意為“最遲在;不遲於”或“在……之前”等。如:
-I will finish my task by nine. 我將在九點鐘前完成任務。
-The plane takes off at 10:00, so you must try to be at the airport by 9:30. 飛機在十點鐘起飛,所以你必須在九點半趕到機場。
2. until用在肯定句,謂語動詞通常是延續性動詞,如stand, stay, talk, wait等,表示主句動作終止的時間。如:
-I waited until he came back. 我一直等到他回來。
-The war lasted until 1945. 戰爭持續到1945年。
如果用在否定句,謂語動詞通常是瞬間性動詞,如open, start, leave, arrive, finish, stop等,強調主句動作開始的時間。如:
-I didn’t leave the boy until his mother turned up.直到這孩子的母親來,我才離開。
-The noise of the street didn’t stop until it was midnight. 街上的噪音直到半夜才停止。
Sources:
http://ask.koolearn.com/topic/show/308996.page
http://www.pearsonlongman.com/ae/azar/grammar_ex/message_board/archive/articles/00016.htm
http://www.engvid.com/by-until/