中国大学MOOC: when a bar of iron attracts other pieces of iron，it ____a magnet，and thus the attraction is called mangnetism.
中国大学MOOC: when a bar of iron attracts other pieces of iron，it ____a magnet，and thus the attraction is called mangnetism.
when a bar of iron attracts other pieces of iron，it ____a magnet，and thus the attraction is called mangnetism. A: will be acted as B: acts as C: is acted as D: has been acted as
when a bar of iron attracts other pieces of iron，it ____a magnet，and thus the attraction is called mangnetism. A: will be acted as B: acts as C: is acted as D: has been acted as
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