哪种结石易在碱性尿中形成（）
A.草酸盐结石
B.磷酸盐结石
C.尿酸结石
D.胱氨酸结石
E.黄嘌呤结石
参考答案：B
We _____ the work on time without your help.
A．hadn’t had finished
B．didn’t have finished
C．couldn’t have finished
D．can’t have finished
其黑便提示上消化道出血量在多少毫升以上
A．10ml
B．20ml
C．30ml
D．40ml
E．50ml
