早期确诊甲状腺功能减低症的实验室检查是()
A.甲状腺抗体的测定
B.TRH兴奋实验
C.血清T3、T4、TSH测定
D.甲状腺扫描
E.骨龄测定
参考答案:C
The square root of 800 is between which of the following integers ?()
A. 21 and 25
B. 24 and 28
C. 27 and 31
D. 30 and 34
E. 33 and 37
动滑轮的游车改变了力的方向,定滑轮的天车起到了省力的作用。