几道关于非谓语动词的高中英语选择题,请说明为什么,Robertissaid_____abroad,butIdon’tknowwhatcountryhestudiedin.A.tohavestudiedB.tostudyC.tobestudyingD.tohavebeenstudyingI’vework

　　几道关于非谓语动词的高中英语选择题,请说明为什么,

　　Robertissaid_____abroad,butIdon’tknowwhatcountryhestudiedin.

　　A.tohavestudied B.tostudy C.tobestudying D.tohavebeenstudying

　　I’veworkedwithchildrenbefore,soIknowwhat______inmynewjob.

　　A.expected B.toexpect C.tobeexpecting D.expects

　　ItissaidinAustraliathereismorelandthanthegovernmentknows______.

　　A.itwhattodowith B.whattodoitwith C.whattodowithit D.todowhatwithit

　　Themanwefollowedsuddenlystoppedandlookedasif_______whetherhewasgoingintherightdirection.

　　A.seeing B.havingseen C.tohaveseen D.tosee