多项选择题科学研究的特征是( )。
多项选择题教师主要通过做好( )工作,促进个体的社会化。
单项选择题— ______ —Yes, a bit cold, though.
单项选择题No sooner had we reached the top of the mountain ______ we all sat down to rest.
单项选择题I don't think it advisable ______.