— We need to           a plan.

— Let's have lunch first. [ ]

A. come up

B. come up with

C. catch up

D. catch up with

微库仑分析中回收率低，正确的处理是（）。

A.重新调整气体流量

B.调整偏压到适当位置

C.重新选择采样电阻

D.减小增益