twifold meaning in English

双重的两倍的
有二形的

The article studying mute are to analyse the formation of the teaching habits of the physical education teachers ; to recognize the twifold features of teaching habits ; to grasp the principle of promotion the teaching habits innovation ; to produce all conditions of the teaching habits innovation ; at last , to put forward the strategies of the teaching habits innovation
研究思路是：剖析体育教师教学习惯的形成；认识教学习惯的双重特征；把握促进教学习惯创新应遵循的原则；生成教学习惯创新的内外条件；最终提出教学习惯创新的策略。