non-obligateBNC²³⁶²¹³⁺¹ 例句 The marked variability of the non-obligate associated manifestations of IFAP syndrome and the overlapping of its clinical features with the other syndromes leads to a challenge in diagnostics. 由于该综合征相关症状的多样性以及与其它综合征症状的重叠性，给诊断带来一定难度。 kns50.chkd.cnki.net