A sound which is capable of distinguishing one word or one shape of a word from another in a language is a__________．

In ______, the only element that can be deleted or removed is the one that was inserted most recently.

Either you or one of your students ______ to attend the meeting that is due tomorrow.

This is one of the best films that _____ this year.

This is one of the best films that ______ this year.

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.

This is one of the most beautiful pictures of scenery that ________displayed here．

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．

 ______ twice a year, whether it is a car or a bus or a truck, is the rule that every driver must obey in this city.