Question

I ________ my key to my office at home, so I had to wait until other teachers ________ to open the door．

1. A.
   had left; came
2. B.
   left; came
3. C.
   has left; came
4. D.
   left; would come

Answer 1

A
本題考查過去完成時(shí)和一般過去時(shí)的比較。leave my key這個(gè)動(dòng)作明顯發(fā)生在had to wait之前，所以為過去的過去，用過去完成時(shí)；而come這個(gè)動(dòng)作是出現(xiàn)在until引起的時(shí)間狀語(yǔ)從句中，應(yīng)該用一般過去時(shí)代替過去將來時(shí)，所以答案為A項(xiàng)。