Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.We have conducted exhausting research into the effe
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.
We have conducted exhausting research into the effects of smartphones on students' behaviour and their academic performance.
A. into
B. academic performance
C. exhausting research
D. behaviour