此句中的never since 與 never before 同義。　　

關(guān)于before與in front of的區(qū)別，《英語常用詞多用途詞典》的before詞條有如下解釋：before表示位置的情形在現(xiàn)代英語中并不多見，尤其是具體的場所或建筑物前，幾乎不能用before，而用in front of：The car is parked in front of the post office. 那車就停在郵局前面。before用于表示位置的情形主要見于按順序出現(xiàn)的場合(如在名單上等)、在某人面前以及某些習語(如before one’s eyes)等。　　

至于 ahead of 的用法，《劍橋高級英語詞典》對此總結(jié)了以下幾種用法：　　

1. If someone is ahead of you, they are directly in front of you. If someone is moving ahead of you, they are in front of you and moving in the same direction.　　

2. If an event or period of time lies ahead of you, it is going to happen or take place soon or in the future.　　

3. In a competition, if a person or team does something ahead of someone else, they do it before the second person or team.　　

4. If something happens ahead of schedule or ahead of time, it happens earlier than was planned.　　

5. If someone is ahead of someone else, they have made more progress and are more advanced in what they are doing.