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举一反三
【单选题】When stars like our Sun die, they bloat to become red giants and then eject gigantic clouds of gas and dust into space. Increasingly, however, scientists found themselves at a profound loss to explain...
A.
explain-the possible way of death of our Sun.
B.
show the two types of red giants.
C.
discuss on the way of red giants to become white dwarfs.
D.
explore the origin of life.
【单选题】化学除锈过程依次为()几道工序。
A.
清洗——除油——除锈——中和
B.
除油——除锈——中和——清洗
C.
除锈——除油——中和——清洗
D.
中和——清洗——除油——除锈