I can not sleep the night before an exam .the前面不需要加介词吗?

I can not sleep the night before an exam .the前面不需要加介词吗? before能做引导词吗,在这句I can't sleep the night before an exam是吗谢谢 英语翻译I can't sleep the night before I take a big exam..Then I I can’t sleep the night before i take a big exam.是不是定语从句 befor` can‘t an exam I sleep night the连词成句 Sleep well on the night before the exam the night before an exam意思 I can not sleep night before…为什么没有at? excited,sleep,the not,night,could,before,I,I,so,was,that连词成句 I can't sleep on the night.I take a big exam.(合并成一个句子） Before the big exams ,I'm always____(sleep) at night 在参加大考前的前一天晚上,我无法入睡i can't sleep the night before__a big exam