Electronic computers, which make it possible to free man from the labor of complex measurements and computations, have found wide applications in engineering.

A．it increases the danger of war
B．it provides services to both the good and the malicious
C．it makes distant communication easier
D．it breaks up the multi-generation household

A．has made letter writing an art
B．has prevented wars by avoiding written communication
C．has made world different from what it was
D．has caused wars by magnifying and extending human conflicts