男性肾盂内结石排出体外需经过哪些狭窄?(3分)
参考答案:尿管起始段、输尿管跨越小骨盆上口处(跨越髂血管处)、输尿管壁内段、 * * 内口、 * * 膜部、 * * 外口。
论述酶与食品色泽的关系。
We arranged to meet at 8:00, but she never ______.
[ ]
A. turned down
B. turned off
C. turned over
D. turned up