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【判断题】
Na 2 HPO 4 的水溶液呈弱酸性(磷酸的 pKa 1 =2.16 , pKa 2 =7.21 , pKa 3 =12.32 )
A.
正确
B.
错误
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皮皮学刷刷变学霸
举一反三
【多选题】在进行()操作时应佩戴有深色镜片的头盔或护目镜
A.
保护焊
B.
等离子切割
C.
氧乙炔焊
D.
磨削或切削
【简答题】horizontal lathes, vertical lathes, turret lathes, copying lathes, automatic lathes, CNC lathes and variety of special purpose lathes
【简答题】岩溶地貌又称___ ,指地下水和地表水对以碳酸盐类为代表的可溶性岩石进行破坏和改造的地貌。分为___ 和___ 两种。岩溶地貌景观有__、___、____、____、__、___、____、_____、__ 等。
【简答题】完形填空。 In a big city, everyone is in a hurry in the early morning. People are 1 the stations, buses and cars. They usually have no time for 2 . People work busily all day. At six o'clock in the evening...
【单选题】The English have the reputation of being very different from ail other nationalities. It is claimed that living on an island separated from the rest of Europe has much to do with it. Whatever the reas...
A.
they are geographically isolated from the European continent
B.
they have nothing to do with the other Europeans
C.
they like to keep quiet among their acquaintances
D.
they tend to be reserved by nature
【单选题】In the early morning all of us stood at the top of the mountain __ east of the city, watching _____burning sun rising.
A.
/; a
B.
the; a
C.
the; the
D.
/; the
【单选题】Ail of us would have enjoyed the party much more if there______quite such a crowd of people there.
A.
weren't
B.
hasn't been
C.
hadn't been
D.
wouldn't be
【简答题】—Why not go out for a walk before breakfast? —Oh,yes. _________ is my favorite time of day. A. In the early morning B. Early morning C. The early of morning D. The early morning that
【多选题】在进行( )操作时,应佩戴护目镜。
A.
使用或处理油漆
B.
使用固化剂
C.
使用溶剂
D.
手工水打磨
【多选题】在进行下列哪些操作时应当佩戴护目镜( )
A.
锤击
B.
钻孔
C.
磨削
D.
切削
E.
车身测量
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