---__________ it is from our own planet Earth to Mars!
---Yes, it takes months to travel to Mars by spacecraft.
| A．How soon | B．How far |
| C．How long | D．How often |
Some precious(珍贵的) animals ____________ because of people’s killing.
A. died from B. put out C. died out
To ______________something is to produce or design it that has not existed before.
A. invent B. discover C. Find
To______________ one’s salary is to make the salary become twice as much as before.
A. double B. increase C. cut
A ______________ is the award given to the winner of a game.
A. gold B. prize C. Present
A __________ is a small book used for writing notes in.
A. guidebook B. notebook C. Textbook