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【单选题】
关于X线量的叙述，正确的是（）A.
X线量是指X线光子的穿透能力
B.
X线量是根据X线特性直接测量
C.
与靶面物质的原子序数Z成反比
D.
与给予X线管的电能成反比
E.
诊断X线范围常用mAs表示
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【单选题】欲配制pH=9．0 的缓冲溶液，应选用的物质为( )。
A.
HAc-NaAc [Ka(HAt)=1．8×10-5]
B.
NH4C1-NH3[Kb(NH3)=1．8×10-5]
C.
六次甲基四胺[Kb((CH2)6N4)=1．4×10-9]
D.
甲酸(Ka=1．0×10-4)及其盐
【单选题】Which of the following is NOT mentioned when Irene talked about the writing part in the project?
A.
They had some historians come and talk to English students about local history.
B.
Students could choose to write in pairs.
C.
They had a third-grade teacher to add notes to tough terminology.
D.
Stories were sent to a historian to make sure that everything was historically accurate.
【单选题】欲配制pH=9的缓冲溶液，应选用的弱酸或弱碱的盐为( )。
A.
NH2OH(Kb=1×10-9)
B.
NH3·H2O(Kb=1×10-5)
C.
HOAc(Ka=1×10-4)
D.
HCOOH(Ka=1×10-4)
【单选题】pH=9 的 NH3-NH4Cl 缓冲溶液配制正确的是( )(已知 NH4 的 Ka=1×10 )。
A.
将 35gNH4Cl 溶于适量水中,加 15mol/L 的 NH3•H2O24mL 用水稀释至 500mL
B.
将 3gNH4Cl 溶于适量水中,加 15mol/L 的 NH3•H2O 207mL 用水稀释至 500mL
C.
将 60gNH4Cl 溶于适量水中,加 15mol/L 的 NH3•H2O 1.4mL 用水稀释至 500mL
D.
将 27gNH4Cl 溶于适量水中,加 15mol/L 的 NH3•H2O 197mL 用水稀释至 500mL
【简答题】The writing of the play is (actual) __________ finished, I had only a few changes to make.
【单选题】According to passage, it is telephone that ______.
A.
has made letter writing an art
B.
has prevented wars by avoiding written communication
C.
has made world different from what it was
D.
has caused wars by magnifying and extending human conflicts
【单选题】What will the counselors at the office do?
A.
Give students hints about writing resumes.
B.
Provide students with jobs that interest them.
C.
Put students in touch with people offering the positions.
D.
Help students pass interviews.
【单选题】欲配制pH=9．0 的缓冲溶液，应选用的物质为()。A．HAcNaAc [Ka(HAt)=1．8×105]B．NH4C1NH3[Kb(NH3)=
A.
欲配制pH=9．0 的缓冲溶液，应选用的物质为( )。 A．HAc-NaAc [Ka(HAt)=1．8×10-5]
B.
NH4C1-NH3[Kb(NH3)=1．8×10-5]
C.
六次甲基四胺[Kb((CH2)6N4)=1．4×10-9]
D.
甲酸(Ka=1．0×10-4)及其盐
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