After a knock at the door, the child heard his mother's voice _     him.       [ ]

A. calling                

B. called      

C. being called            

D. to call

肌内注射的操作不妥的是（）。

A.注射前做好解释

B.取髂前上棘和尾骨连线的外上1/4处为注射部位

C.推药液宜慢

D.注射油剂，针头宜粗长

E.刺激性强的药液后注射