月球引力是地球引力的六分之一,一个90kg的宇航员,在月球上重约 N(g=10N/kg),该宇航员从地球到达月球后质量 (选填“变大”“变小”或“不变”).
My mom gave me this computer as my (sixteen) birthday present.
David feels very proud to be a member of the school volleyball (队).
It is not (礼貌的) to make too much noise while eating or drinking.
Lulu's best friend never gives up her (梦想) of being a teacher.
If you would like to (讨论) the matter further,please call me.