Question

5. The old couple have been married for 40 years and never once        they        (quarrel) with each other.

Answer 1

5. have;quarrelled否定词(如该句中的never) 放在句g'时，应用部分倒装。这类副词有never,hardly,seldom,scarcely,lit?tle等。句意：那对老夫妇结婚已经四年了,却连一次架也没吵过。