有一瓶无色液体,某同学说可以往溶液中滴加酚酞试液,判断其酸碱性.该环节属于( )
A:提出问题
B:作出猜想
C:设计实验
D:反思评价
图1至图4中,反映“澶渊之盟”订立双方政权对峙的是( )
____ .
My father is a teacher. He is always strict _______ his students.