保险产品不同于其它产品在于保险产品的()。
A.无形性
B.潜城性
C.可替代性
D.长期性
参考答案:A
I was too excited to fall _____. I was still ______ until 11 o'clock last night.[ ]
A. sleepy; awake
B. awake; sleep
C. asleep; awake
D. awake; asleep
在零件图中,不可见轮廓线用()线表示。
A.粗实
B.细实
C.波浪
D.虚