He often watches people ________ by our class. [ ]
A. pass
B. passes
C. to pass
答案:A
肝脏直接参与多种维生素的代谢转化,可将维生素D1转化为()
A.1,25-(OH)2-D3
B.1-(OH)-D3
C.25-(OH)-D3
D.2,25-(OH)2-D3
E.1-(OH)2-D4
从安全与舒适角度考虑,楼梯的坡度应以( )为宜。
A.20°~45° B.26°~45° C.26°~35° D.33°~45°