问题
选择题
23. Tom had to be told two or three times ________ he could remember what the teacher said.
A．before
B．when
C．until
D．As
答案
答案：A
23．A(解析：考查连词。before "到……为止；在……之前"when“当……时候"until"直到……为止”as“当……时候”，until强调动作的延续性，其中tell并非延续性动词，另根据句意“老师说两三遍之后汤姆才能记住。”因此选A。)