一 7" 26ppf L-80 x 9 5/8" 43.5 ppf Liner Hanger Set, Tandem Cone, Hydraulic Set with BTC connections.
这句话的翻译中,Tandem Cone怎么翻译呢?
二 Provision of a fully qualified, competent and experienced field service engineer ( on Call out Basis)
这句的翻译中on Call out Basis怎么翻译呢?