The first elecators were controlled by_______ . A: computer programme B: special equipments C: electrical engineers D: human operators

How would you like to pay, in cash or by_______? A: credit card B: ID card C: passport D: key card

It was only by_______ together days and nights of consistent effort, did the author published his famous work. A: getting B: stringing C: weaving D: putting

The logical relationship in a title can be shown by_______ A: using “:” to introduce a subtitle. B: avoiding abbreviations. C: using a question. D: using appropriate prepositions between the noun phrases.