试题题干
Translate the following sentence into Chinese.
But their ideas sometimes had to wait for years before they were understood sufficiently well to be of practical use.
参考答案
试题解析
考点：wait for years等好几年；be understood sufficiently被充分理解；be of practical use得以实际运用
句子结构：句子主干为their ideas sometimes had to wait for years，before引导时间状语从句。