某初中一个学期的数学总平均分是按扇形图信息要求进行计算的，该校胡军同学这个学期的数学成绩如下：则胡军这个学期数学总平均分为（　　）

下列防腐措施中，利用原电池反应使主要金属得到保护的是           (　　)

下列实例中属于机械能转化为内能的是 （  ）

对于低温诱导洋葱染色体数目变化的实验，不正确的描述是（  ）

A: How was your vacation, LiLei?
B: ____  I went to Beijing with my parents.
A: Cool! Where did you go in Beijing?
B: We went to the Summer Palace, the Palace Museum and so on.
A: ____ 
B: It’s interesting. I really like the Palace Museum. It has many beautiful things from different dynasties.
A:____ 
B: Yes, I did. I saw Jackie Chan on the Great Wall. And I got his autograph.
A: Wow, that's great! Could you show me his autograph?
B: Yes, sure. ____