将2μg·mL-1的标准铜溶液喷入火焰,在324.8nm波长处测得吸光度为0.22。计算此原子吸收光谱仪测定铜的灵敏度。
第1题
In the United States, people usually spend about 80-90% of our time inside buildings.
A.Y
B.N
C.NG
第2题
Which of the following kills the most people in the United States?
A.Accidents.
B.Heart disease.
C.Cancer.
D.Smoking.
第3题
How many terms can a president in the United States be elected to at most?
A.1.
B.2.
C.3.
D.4.
第4题
How many terms can a president in the United States be elected to at most?
A.1.
B.2.
C.3.
D.4.
第5题
What does a house mean in the United States?
A.It is a dream which many people can hardly realize.
B.It is so expensive that many people cannot really buy them.
C.It is the most important property that many people try to buy.
D.It doesn't belong to people if they can't borrow money from the bank.
第6题
How many people are there in the United States in 1987?
A.259 million.
B.117 million.
C.175 million.
D.240 million.
第7题
(Many children) in the United States (spened)(most of) their time (to watch) TV.
第8题
第9题
How many people are there in the United States in 1987?
A.259 million.
B.117 million.
C.175 million.
D.230 million.
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