每天早上他都会在后院练习十分钟的空拳训练。

Every morning he spends ten minutes ___shadowboxing in his backyard.

在比赛前，拳击手经常进行假想对手训练来提高反应速度。

Before the match, the boxer likes to ___shadowbox to improve his reaction speed.

博物馆用立体展示盒展示珍贵的古董。

The museum displays rare antiques in a ___shadowbox.