The old couple have been married for 40 years and never once _______ with each other.
A、theyhadquarreledC
本題考查的是倒裝結構的用法。第二分句中因有否定副詞never提前，故應用倒裝結構;第一分句中的havebeenmarried已限定了時態，據此可排除D項。
ThedivisionofEnglishintoOldEnglish,MiddleEnglish,andModernEnglishisnonconventionalandnotarbitrary.
Thebasicunitinthestudyofmorphologyis______.
Ifpaymentisnotreceived,legalactionwillbeouronly________.
Theothertimingsystembelongsinourinternalclocks，which，left________，wouldtiethebodytoa25-hourrhythm.
Acompoundisthecombinationofonlytwowords.
