The old couple have been married for 40 years and never once _______ with each other.
A、theyhadquarreledC
本题考查的是倒装结构的用法。第二分句中因有否定副词never提前，故应用倒装结构;第一分句中的havebeenmarried已限定了时态，据此可排除D项。
Ifpaymentisnotreceived,legalactionwillbeouronly________.
Fromthesociolinguisticperspective,aspeechvarietyisnomorethanadialectalvarietyofalanguage.
Itwasasmallplacethencomparedto_______itisnow.
The other timing system belongs in our internal clocks，which，left ________，would tie the body to a 25-hour rhythm.
Idon’tmind_______thedecisionaslongasitisnottoolate.
