【单选题】

It was wonderful up there. Ralph wanted to reach out and (21) a star, for they (22) so close. He could see the earth getting smaller and smaller.

The ship circled around a made star called Mars (火星), and his space friends (23) Ralph understand that this was their home.
He wanted to ask all kinds of (24) , but no one could answer him. There was nothing to eat or drink. There people had only (25) colours pills which they can eat (26) they were hungry.
Soon it became (27) harder fin Ralph to breathe than he felt at first. He felt (28) light that he could not even stand (29) his own feet. "If I could only have some water," he (30) , "and a ride back down to the earth!"
The spacemen knew that it was (31) for Ralph to leave. He could not live up there (32) longer without special air or suit like theirs. So they took him to a part of the ship where there was (33) enough for just one man.A、door closed over his head and (34) a minute Ralph was flying down to the earth in his own rocket ship.
Suddenly he felt the rocket (35) down and then stoppeD、He was back on the earth.
A．in
B．after
C．for
D．before