Question 5: In studying this planet, astronomers have found that life may be possible on Mars.
The first _____ of this is that Mars has seasons, just like Earth.
A. indication B. print C. mark D. trace
1000 câu khó mục tiều 9+ Tiếng anh ôn Tốt nghiệp THPT Quốc Gia (Lesson 2)