This book is said to be a special one, which ______ many events not found on other history books. 　 [ ]

With the development of reform of education, many teachers are ________ some more effective methods of teaching. [ ]

No matter ____ he is, he must ____ and don’t use his cell phones in the class. [ ]

The machine has been used much too long.________it doesn’t work well sometimes.[ ]

Why did you go back upstairs?— I thought I had left the window ______. [ ]