良好师生关系的特征是()。
A.情感支持
B.民主平等
C.尊师爱生
D.严格要求
E.教学相长
参考答案:B, C, E
解析:良好的师生关系的特征为民主平等、尊师爱生和教学相长。
I want to write to John, but I don't know ________. [ ]
A. what his e-mail address was
B. what is his e-mail address
C. what his e-mail address is
D. what was his e-mail address
重碳酸盐硬度又称为()。
A、暂时硬度
B、永久硬度
C、负硬度