按载体形式的不同，文献可以分为纸质和非纸质文献，以下属于非纸质文献的有（ ）。

Many boys enjoy _______ football, basketball or baseball

－ What does the sign over there read － “No person ________ smoke or carry a lighted cigarette, cigar or pipe in this area”

1_____education is the instruction that occurs when the instructor and students are separated by distance or time,or both

If a boy or a girl has grown up in a home with sharing tasks and decisions，he or she will probably______.

Either he or I ______to the airport.

Duty is an act or a course of action that people __________you to take by social customs, law or religion.

Duty is an act or a course of action that people ______you to take by social customs, law or religion.

Project ______is an uncertain event or condition that，if it occurs，has a positive or a negative effect on at least one project objective，such as time，cost，scope，or quality．

_____city do you prefer, Shanghai or London?

It will be a relief over the death of a friend or a relative if the friend or relative dies from ______.

Hurry up, or you ______ catch the train.