Mark the letters A, B, C, or D on your answer sheet to show the underlined part that needs correction in each of the following questions
(A) Because of the expense of (B) traditional fuels and the concern that they (C) run out, many countries have been (D) investigating alternative sources of power
A. Because of
B. traditional fuels
C. run out
D. investigating
Đáp án : C
Concern = sự lo lắng. Run out = cạn kiệt. Việc có thể cạn kiệt là có thể xảy ra trong tương lai -> Concern that they may/will run out = sự e ngại rằng chúng có thể cạn kiệt