据报载我国最近合成新的同位素,其中一种是18572Hf(铪),它的质量数是( )
A.72
B.113
C.185
D.257
答案:C
______ from the top of the tower, the south foot of the mountain is a sea of trees.
A.Seen
B.Seeing
C.Having seen
D.To see
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