Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 12)

Not only _____________ to determine the depth of the ocean floor, but it is also used to locate oil

16/50

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Not only _____________ to determine the depth of the ocean floor, but it is also used to locate oil.

seismology is used

using seismology

is seismology used

to use seismology

Giải thích

Đáp án C