除指定者外，临时加挂客车原则上应挂在列车尾部，由始发站挂至终点站时，可在（）加挂。
A.列车中部
B.列车前部
C.列车尾部
D.列车编组中
参考答案：D
I told my mother I wasn't worried about my exam. But in fact I ___________. [ ]
A. did
B. was
C. have
D. had
（）不属于食品的三要素之一。
A、质量可控
B、营养
C、安全
D、享受
