a long vertical tube containing a set of mirrors which gives you a view of what is above you when you look through the bottom of the tube
发音
例句
1. The captain aligned the periscope on the bearing. 船长使潜望镜对准方位。 2. Now, peering through the periscope he remarkes in businesslike tones. 现在,他一面从潜望镜里观察,一面用精干踏实的口吻说话。