如图，已知AB=A₁B，A₁C=A₁A₂，A₂D=A₂A₃，A₃E=A₃A₄，∠B=20°，则∠A₄=____度．

建国初期起临时宪法作用的是（   ）

某校组织了九年级学生英语口语模拟测试，现从中随机抽取部分学生的口语模拟测试成绩统计如下．

根据上面提供的信息，回答下列问题：

（1）扇形统计图中的圆心角a=____ °；

（2）统计表中样本容量m=____ ；

（3）已知该校九年级共有400名学生，如果口语成绩达28分以上（含28分）为优秀，请估计该校九年级学生口语成绩达到优秀的总人数____ 

东营园博园是全省自然与文化的缩影，是休闲旅游的好去处，小明和妈妈在园博园骑双人自行车游玩，如图所示，以妈妈为参照物，小明是____的（选填“运动”或“静止”）；若骑行2.7km路程，用了0.5小时，则平均速度为____m/s．

阅读理解，判断文后句子的正误。

    My name is Amy. Tomorrow is Saturday. We have no classes. My parents aren't going to work, but we are going to be very busy tomorrow. My mother is going to buy something for next week. My father is going to visit my aunt and uncle. I'm going to go to the bookstore by bus. Then I'm going to buy a dictionary. Tomorrow evening we are going to visit my grandparents and have a big dinner. After that we are going to go to the cinema. I think we are going to have a nice weekend.