下列哪一项不是湿啰音的特征（）
A.持续时间较短
B.强度性质易变
C.多呈断续性
D.吸气时较为明显
E.咳嗽后可减轻或消失
参考答案：B
Jenny was very sad over the loss of the photos she had shot at Canada, ____ this was a memory she
especially treasured.[ ]
A. as
B. if
C. when
D. where
要维持镁剂除硅效果的石灰加入量，最佳PH值通常介于（）之间。
A、10.1-10.3
B、8.5-9.5
C、9.0-10.0
D、10.5-10.8
