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

Câu hỏi

The smart cities in the future will operate ________ with advanced transportation systems.

A. efficient

B. efficiently

C. efficiency

D. effect

Đáp án
B. efficiently

Câu hỏi thuộc Bài tập:

E11- Unit 3- Test for Unit