问题补充：
There were already five people in the car but they managed to take me as well . It a comfortable journey .
A. can\t e
B. shouldn\t be
C. mustn\t have been
D. couldn\t have been
答案：
A. can\t e
B. shouldn\t be
C. mustn\t have been
(答案→)D. couldn\t have been
解析：could表示对过去事情的推测，用于否定句或疑问句。
