An extra head shouldn't make a difference. 额外的头没有差别的。
After six weeks, participants in the research took another series of tests and no difference was found between the ginkgo group and the placebo group. 但是六周后，参与研究的人再度进行一系列的试验，却发现服用银杏与服用安慰剂的两组人之间并没有差异。
There is no significant stress difference in the dentin for glass ionomer restoration when compared with that of an opening incisor. 凡以玻璃水门汀为补缀材料之门齿，在应力分布的表现上皆与根管治疗后尚未补缀之门齿相同没有差异。
