现在彗星被认为是一个主要由岩石构成的冰冷的土球。 而不是1950年哈佛大学天文学家Fred Whipple假设的盖着土的冰球。
They are now seen as "icy dirtballs", dominated by rock, in contrast to the "dirty snowballs" hypothesised by Fred Whipple, an astronomer at Harvard University, in 1950.
该机主要用于经济林、观赏林苗木的挖掘移栽和胸径12公分以下的半成材林、淘汰林的移栽与采伐，能够保持土球的完整，便于运输，提高成活率。
The machine can adapt small wood and view and admire little trees remove, below 12 centimetres trees remove. And can protect the earth full, transportation convenience, and good survive.
有人曾经怀疑他极端的握拍方式以及强劲有力的上旋球等适合土场作战的技术是否能在其他赛场上所向无敌。
Some doubted whether his extreme grip and massive topspin game which is made for clay could shine on other surfaces.
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