一般说钢材的含碳量越高，磁导率越低，矫顽力越低，达到磁饱和所需要的磁场强度越弱
参考答案：错
选择正确的答语。
1. Let's eat the birthday cake. [ ]
A. Me too.
B. Great!
2. How old are you?
A. I'm eight.
B. I'm fine.
3. How many dolls? [ ]
A. I'm five.
B. Four.
4. — How are you?
— [ ]
A. Fine, thank you.
B. Yes, I am.
5. — Where is Zoom?
A. There is Zoom.
B. He is reading.
卵巢功能进一步衰退，生殖器官逐渐萎缩的时期称为（）
A.幼年期
B.青春期
C.性成熟期
D.更年期
E.老年期
