______ to nuclear radiation, even for a short time, may influence genes in human bodies.

A．Exposed

B．Being exposed

C．To expose

D．Having exposed

造成剖宫产术后子宫切口出血的原因不包括

A．切口延裂

B．切口过低或过高

C．切口缝合过松

D．切口缝合过紧或过密

E．子宫右旋明显，做切口前子宫先复位