Notes of a word-watcher, Hanching Chung. A first port of call for English learning.
NASA has tasked Boeing and Northrop Grumman with forming a roadmap to Mach 4 airliners
注意：只有此網誌的成員可以留言。
沒有留言:
張貼留言
注意：只有此網誌的成員可以留言。