若三直线2x+3y+8=0，x－y－1=0和x+ky=0相交于一点，则k＝
-1/2
治疗TMP所致巨幼红细胞性贫血时，宜选用（）
A.口服叶酸
B.肌注叶酸
C.肌注甲酰四氢叶酸钙
D.口服维生素B12
E.肌注维生素B12
When magnesium sulfate is administered to a client in labor, its action occurs at which of the following sites
A．Neural-muscular junctions.
B．Distal renal tubules.
C．Central nervous system (CNS).
D．Myocardial fibers.
