3、fjusttokeephimself________.A.tobecoveredB.coveredC.coveringD.tocover【解析】 本题空格处应填入与keep的宾语构成补足语的结构,即补充说明himself,由于cover和himself之间为被动关系,故cover应用过去分词形式。【答案】 B3.Themachinehasbeenusedmuchtoolong.________itdoesn'tworkwellsometimes.A.It'snowonderthatB.There'snodoubtifC.It'sunlikelyD.That'sbecause【解析】 A