They put forward a lot of plans at the meeting, none of _______ were carried out in their work.

A．which

B．them

C．what

D．that

氢火焰检测器的检测依据是（）。

A、不同溶液折射率不同

B、被测组分对紫外光的选择性吸收

C、有机分子在氢氧焰中发生电离

D、不同气体热导系数不同