在太空舱里，宇航员可以体验到完全失重的感觉。

Inside the space capsule, astronauts can experience being completely ___weightless.

宇航员在太空中漂浮时感觉完全失重。

Astronauts feel completely ___weightless when floating in space.

在严肃的讨论中，他的玩笑话显得毫无分量。

His jokes seemed ___weightless during the serious discussion.