___ the silence of the pauses, we could hear each other’s breathing and could almost hear our own heartbeats.

A．In

B．For

C．Under

D．Between

关于焦点的散焦值叙述错误的是（）

A.描述焦点极限分辨力随负荷条件相对变化的量

B.管电流大则焦点变大

C.一般大于等于1

D.散焦值越大越好

E.散焦值等于1时焦点成像性能稳定