[ Vocabulary ]
a physical system that does not allow transfer of matter in or out of the system
A. conservation of matter
B. closed system
C. reactant
D. chemical reaction
Select your answer:

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Idioms › ViewTo “iron out” means to ___.
a. complete small details
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Grammar › View
Nam’s father (get) _______ up at 4 o’clock.
A. gets
B. getting
C. got
D. get
