Regular exercise helps prevent weight.
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Every year nine millionvisitors come to the city.
The president has already given his to the plan.
Shefor her work in promoting friendship between the two countries.
在分光光度法中,宜选用的吸光度读数范围为 ( )
A. 0-100
B. 0-1
C. 0.2-0.8
D. 0-∞
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