They talked about the contradictory theories of the ____(起源) of life.
人没有萤火虫的荧光,仍可以将黑夜变成白昼;人没有鸟的羽翼,仍可以飞上蓝天……这说明( )
Chinese like ____ (饺子) very much.
下列实验操作不当的是( )