envelopen.信封；壳层；封袋envelope curve包络,包迹envelope cursor包络线光标envelope factor包迹因数envelope method包络法,包迹法envelope system纸袋式资料整理法envelope format包封格式envelope viewer包线指示器,包络观察器envelope feeder信封送纸器envelope manila马尼拉信封纸enveloped virus有包膜病毒

1. A whole battalion of soldiers surrounded us in a tight ring.
   整个军队把我们紧紧地包围在包围圈中。
2. Hopefully it would help contain the oil in a small area.
   希望这一做法能将原油包围在一个小的海域内。