英语必修5人教新课标unit4同步练习（2）及答案
一、用方框内所给短语的适当形式填空
defend against/protect against/concentrate on/devote oneself to/get all the facts straight
1. we’re well prepared to any surprise attack.
2. the polluted air, the old lady always wear a mask over her face.
3. your study if you want to catch up with the class.
4. he
