There is no possibility ________ he will keep his word．He is always telling lies.

A．how

B．whether

C．when

D．that

飞灰采样应尽可能在（）且采样截面前后应有适当直段。

A.水平烟道气流稳定处

B.垂直烟道气流稳定处

C.水平与垂直烟道结合处

D.烟气挡板附近