问题
选择题
Tom didn't go to school_______ this morning because he oversle
pt.
A．at once
B．on time
C．by accident
D．at present
答案
答案：B
考查词语辨析。at once “立刻；马上”；on time“按时”；by accident“偶然”；at present“目前;现在”。句意为“汤姆今天早晨没有按时上学，因为他睡过了头”故选B.
