hold back 踌躇,退缩；阻止,抑制；隐瞒,保守(秘密等)
mixed-ability (班级、教学法等)不分程度差异的,混合编制的
We find that bright children are rarely held back by mixed-ability teaching.我们发现聪明的孩子在不分程度差异的教学中很少退缩.