老年人体内蛋白质的合成能力差,同时对蛋白质的吸收利用率下降,容易出现()氮平衡。
参考答案:负
进行全口义齿修复,患者微笑时,上唇微笑线到平面的直线距离约为上中切牙的()
A.切1/3长
B.切2/3长
C.中1/3长
D.中2/3长
E.颈1/3长
-- Do you still remember when you first met John?
--- I can’t quite remember, but I’m sure it was ______ Friday afternoon because we were at ______ school for a meeting.
A./; the
B.the; /
C.a; /
D./;a