It'snecessaryforthephubbers(低头族)to   thetimetheyspendon...

问题详情：

It's necessary for the phubbers(低头族)to   the time they spend on their smart phones.

 A. cut in  B. cut off    C. cut down   D. cut up

【回答】

C

知识点：动词和动词短语

题型：选择题