. If you think that the illness might be serious, you should not ______ going to the doctor.

A．put off

B．set about

C．hold back

D．give away

现在大多采用罐车泵油集输方式，在泵油车泵油时，采油工必须在现场量取泵前和泵后储油罐内的液面变化，算出泵油量，以便准确计量（）。