Какое слово грамматически и по смыслу можно вставить одновременно в три предложения. Mother ... is the thing that every person is obligatory to know. Fortunately nobody noticed my slip of the ... during the conference. These te...

Какое слово грамматически и по смыслу можно вставить одновременно в три предложения. Mother ... is the thing that every person is obligatory to know. Fortunately nobody noticed my slip of the ... during the conference. These terrible words seemed to be on his ... already but fortunately he could hold on.