Question

【题目】I couldn’t work out this problem ________ my teacher helped me.

A. before B. unless C. because D. until

Answer 1

【答案】D

【解析】

试题分析：句意：直到老师帮助了我我才解答出这道题。根据句意及题干分析此题考查not...until结构，是直到……才……的意思，故选D。