2017年9月l2目，乙公司从甲公司处租赁了一套办公家具，租期一年。年12月282017日，乙公司以自己的名义将该套家具出售给不知情的丙公司，双方签订了办公家具买卖合同，丙支付了l0000元预付款，但家具尚未交付。甲于2018年1月6日对买卖合同进行了追认。
问题：
(1)买卖合同的当事人是谁?为什么?
(2)买卖合同于何时生效?为什么?
(3)若甲未追认买卖合同，乙应当对丙承担什么责任?为什么?
Inordertobuyanewcar,youshouldatleast______onehundreddollarsaweek.
Ifyou’resittingaroundalonelycampfireatnight,thehowlofawolfcansoundpretty______.
WhyweretheFrenchtroopsinCanadadefeatedbytheBritishduringtheSevenYears'War?
肺炎患儿的护理措施是（）
Thesadconditionofwomenworkingashouseservantsaroundtheworldreceivedmuchmedia_____earlythisyear.
Pleaseremindme_______herthisnote.
Homingpigeonisusefulasa______carrierbecausewhentakenfromhome,itwillreturnatthefirstopportunity.
Two-thirdsofhisproperty_____lostinthefire.
Decisiononwhetherthemessageisrightorwrongshouldatleastcomeafter_____whatthemessageis.
Itmakesgood________tobringanumbrella;itseemstoberainingtoday.