We played tennis _______ four o'clock. (by, until) 　　

■填 until，表示“一直持續(xù)到……”，英語(yǔ)詞典的解釋是：If something happens until a particular time, it happens during the period before that time and stops at that time.  　　

I am afraid she can't catch up with the others in our class _______ the end of this term. 　　

■填 by，表示“……之前的任何一個(gè)時(shí)候”，它的意思是not later than (a time)，簡(jiǎn)單地說(shuō)，它與 before 意思相似。