1. _____ you are leaving tomorrow, we can eat dinner together tonight.

A. For  B. Since  C. Before  D. While (全国四级,99.6-58)

老师们好, 回看这道题时，突然想到before为什么不能选。题目倒是知道要选since.  for在牛津高阶第四版里指出“conj (dated or fml 旧或文) (not used at the beginning of a sentence 不用于句首) because 因为; 由于:。”

下面是一些例句

纽约时报：
• “This sets a dangerous precedent,” he said. “Today it's telecoms and Huawei. Tomorrow it could be your industry, your company, your consumers.”

谷歌网页 / 图书：

•  "Great, we can eat dinner together before you go home," Jason says, starting the car. "Alright". The following day starts off the usual way.

•  Maybe , before you go home we can talk a little more .

coca：

• How you think you're gonna do there? She's thinking: " I'm getting out before you're getting out. " " You're dead, you're dead, I'm gone. "