问题补充:
As is known, mobile phones make it possible for people to each other conveniently.
A. keep in touch with
B. get in touch
C. lose touch
D. be concerned
答案:
(答案→)A. keep in touch with
B. get in touch
C. lose touch
D. be concerned
解析:本题的含义为众所周知,手机使人们彼此之间很方便保持联系,keep in touch with表示与某人保持联系的含义,故本题选A。