操作人员是指直接从事基本生产和辅助生产的人员，下面不属于操作人员的是（）。

A.钳工

B.化验工

C.装卸工

D.餐厅服务员

With the development of modern science and technology you can take your favourite radio

programmes with you on the move and listen     you like．     

A．whenever

B．however

C．whatever

D．whichever