Câu hỏi:

Read the text carefully and then choose the correct answer

Forty - two years ago, two Americans landed on the moon, taking the human race to another planet for the first time. On July 16, 1969 Armstrong, Aldrin and Collins climed into Apollo 11 .The unit’s Saturn V rocket, equipped with the most powerful engines ever built, blasted them into space. Their trajectory took them around the Earth and toward the moon when a third-stage rocket fired. Two modules-the Eagle, for landing, and the Columbia, a command and service center- entered the moon’s orbit on July 19. Neil Armstrong, Buzz Aldrin, piloting the Eagle landing module, stepped down on the moon on July 20,1969.The third US astronaut ,Michael Collins ,was in the orbiting command module overhead. “That’s one small step for a man, one giant leap for mankind”, said Armstrong. The words were seared into the memories of the 600 million some people- about 1/5 of our planet’s population at that time-who watched the broadcast transmitted from the lunar surface. And for a time it seemed the impossible was just the beginning.

Relative pronoun who refers to…………