可以在化学实验室穿着的鞋是（）
A.凉鞋
B.高跟鞋
C.拖鞋
D.球鞋
参考答案：D
It is written clearly in the requirements that all passengers _______ check onto board thirty minutes before the plane takes off．
A．may
B．can
C．will
D．shall
肾积水的声像图表现（）
A.肾盂分离中间为液性暗区
B.肾盂分离中间为液性暗区，液性暗区与输尿管相通
C.肾盂分离中间为液性暗区，液性暗区与输尿管相通，液性暗区不相通
D.肾盂分离中间为液性暗区，液性暗区与输尿管相通，液性暗区互不相通，液性暗区液腔饱满
E.肾盂分离中间为液性暗区，液性暗区与输尿管相通，液性暗区液腔饱满
