"shift+D" can duplicate 1 model ,but how duplicate several models? Thanks.

If you mean make multiple copies of one object, you could use the array modifier. Just apply the modifier when you are satisfied with the number. If you mean make copies of different objects at the same time, just shift + right click to add them all to the selection and then make the copy.

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"The true sign of intelligence is not knowledge but imagination".

Albert Einstein

Thanks laser.But is there any way to make multiple copies of one object? I need scattered obj ,here and there .To use array modifier that can make obj uniform.

Is this what you are talking about? https://www.youtube.com/watch?v=uZ_Qu0-ozbo

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"The true sign of intelligence is not knowledge but imagination".

Albert Einstein

Thanks laser.