请问jack has been busy _ his report.这句话中应该填什么

请问jack has been busy _ his report.这句话中应该填什么 a jack has been unplugged -jack is busy packing luggage -yes he___for America on vacation A.leaves B.left C.is leaving D.has been away Jack ()a teacher for months.A.has becomeB.has turnedC.has changedD.has been helen jack for 7 yearsA has been married to B has been married to C has married D has been married to空位于helen和jack之间， jack has been dead for three years为什么用被动jack已经被死了三年? 过去分词beenHe has been busy since last week为什么不直接用busy的过去分词,而是用been Jack‘s grandmother ___for more than twenty years.A has dead B has been died C has been died Jack __a postman for about 6 years.a has become b.has returned c.has changed d.has been Jack ____a postman for about six years.A has become B has turned C has changed D has been I have been busy yesterday afternoon为什么要用have been busy而不用have busy主要想问的是什么时候现在完成时里动词前要用been,也就是have been ...例如还有 ：She has been sick since last month. jack has lost his job and been worse off than everbeen 要在been前加个has吗? Believe it or not,Jack has been to Beijing.为什么要用has been to,不用was to 英语翻译请问为什么不是 has been opened? 请问have been 和has been有什么区别 Tom has been busy with his work ________ Monday.A.from B.since C.for 3.Jack has already been to Water World.划线部分：water world.划线提问 Jack has been collecting coins since two year ago.（用how long提问.）