A new term has begun. Teachers are 1 about the fact that new students are not easy to handle. They like to bring cellphones and MP3 players to school. What is2，some students even use cellphones to do with out-of-class matters in class，or sometimes just for fun. Some other students listen to MP3 players when they are having a lesson that they are not interested in.
Are these new students really that3? ’Yes，’ says Delaney Kirk，a professor at Drake University.4she adds it’s not their fault. Instead， the things that they bring into school---cellphones，MP3 players and so on --- and the teachers are to blame. Kirk first began thinking about students’ manners six years ago. ‘I had my first class in which students were sleeping or talking to each other. It seemed that learning well 5 nothing to do with them，’ she says. ’At first，I got worried about this，but then I said to myself， "You’re teaching 6，and you need to  manage this…These students need to know more about manners. It’s time to help them develop some good 7 . They shouldn’t waste time doing nothing when they are young. Sooner or later，they might regret the time they have wasted."’
Kirk also   8 a list of suggestions to help teachers better manage their classes. The following are among her suggestions：
●  Tell students how they will benefit by taking the class. On the first day of class，emphasize its importance9giving some homework that students must turn in next time.
●  Do not allow them to bring cellphones and MP3 players to the class at all.
■  Decide10formal and informal the class will be.

读等高线地形图（如图），完成下列要求。

化简分式 $\frac{2a-4}{a^2-4}$÷ $\frac{2a}{a^2+4a+4}$﹣1，并选取一个你认为合适的整数a代入求值．

如图所示，∠1的内错角是____ 　，∠B的同旁内角有____ （只写一个）