back stopping

• 上向梯段回采

back stopping的英文翻译是什么意思，词典释义与在线翻译：

英英释义

名词 backstop:

1. (baseball) the person who plays the position of catcher

2. (baseball) a fence or screen (as behind home plate) to prevent the ball from traveling out of the playing field

3. a precaution in case of an emergency