【C20】______A．worryB．fearC．carelessnessD．hard work

塔筒筒壁的混凝土验算等级不应低于______。A．C30B．C25C．C20D．C15

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（1）a＋18=______＋______　　　a×15=______×______（2）m×2.5×0.4=______×（______×______）（3）（a＋b）×C=______×_____

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It is the director, and not the members of the board, ______ the most.A．who worryB．whom wo

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【C20】______A．withB．offC．beforeD．from

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______, the instruments would be damaged.A．If having handled carelesslyB．To handle careles

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57._________A. hopeB. fearC. waitD. look

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_________(57)A.hope B.fearC.wait D.look

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