下列标准件说法中不正确的是（）

A．国家标准对标准件的画法作了简化和规定

B．国家标准对常用零件的结构形状、规格等作了具体规定

C．销和键都是标准件

D．国家标准对齿轮、弹簧等常用零件的一些常见结构和重要参数作了规定

The nurse is teaching parents how to reduce the spread of impetigo. The nurse should encourage parents to （）.

A．teach children to cover mouths and noses when they sneeze.

B．have their children immunized against impetigo.

C．teach children the importance of proper hand washing.

D．isolate the child with impetigo from other members of the family.