题目

GMAT CR
Since the invention of digital readout,machine designers have rushed to replace conventional dials and gauges with digital units.Yet the digital gauge has drawbacks in somesituations.Since it presents an exact numeric value,it must be decoded andanalyzed by a human operator; its meaning cannot be read in an instantaneousscanning.An analog dial or gauge can be marked with red to alert the operatorwhen a value is entering a danger zone; a digital gauge cannot.And it isdifficult to tell whether a digital readout is increasing or decreasing overtime,while the up or down movement of a pointer on an analog gauge can bequickly and easily observed.
The author of the passage above would probably recommend the use of digital gauge in cases when
I.warning of a sudden riseor fall in value is needed
II.anoperator must read and interpret several gauges within a few seconds
III.aprecise numeric value is essential
(A) I only
(B) III only
(C) I and IIIonly
(

提问时间：2021-04-01

答案

前面讲了it presents an exact numeric value(它显示准确的数值）,所以当a precise numeric value is essential（精确数值至关重要）时,当然要用digital gauge.这就是选B的原因.

而前面还讲了模拟仪表可以很容易地看出升降趋势,数字仪表看不出来,所以不能选A
it is difficult to tell whether a digital readout is increasing or decreasing overtime, while the up or down movement of a pointer on an analog gauge can bequickly and easily observed.