Question

Scientists are working hard to make _______ possible for people to live on Mars in the future.

A．it

B．that

C．this

D．one

Answer 1

A

试题分析：句意：科学家们正在努力工作，使将来人们在火星上生活成为可能。考查句型：make it adj to do sth,故选A。 
考点: 考查代词的用法。