Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions:

The basic elements of public-opinion research are interviewers, questionnaires, tabulating equipment, and to sample population.

 

Suy nghĩ và trả lời câu hỏi trước khi xem đáp án

ATNETWORK
ADMICRO
YOMEDIA
ZUNIA9