互动封闭仿真课堂1、智能交互 2、电子板书式视频教学 3、5分钟一次互动问答 4、封闭课堂
原则十、 非谓语动词的否定原则是在非谓语动词前加not，有not to do, not doing, not having done, not to have done几种形式
例23______that he was in great danger, Eric walked deeper into the forest.
A. Not realized B. Not to realize C. Not realizing D. Not to have realized
解析： 本题考查doing的否定形式not doing，答案为 C。
例24. What worried him most was ______ to visit his sick child.
A. his being not allowed B. his not being allowed
C. his not allowing D. having not been allowed
解析：本题考查being done的否定形式not being done; his 为not being done的逻辑主语，所以答