If it's a smaller window you could remove the backing paper entirely.

如果窗户较小，你可以将贴膜背面的纸全部撕掉。

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Backing paper: a base layer to give strength or support to a top layer.

托底纸：用来支撑面层的纸以啬强度或承托面层。

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We then flip down the top piece, peel back the backing paper from the film and cut it off.

之后我们将顶部翻转过来，撕开贴膜背面的纸，将其剪掉。

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Ubisoft is finally backing down, according to an interview with Rock, Paper, Shotgun.

FORBES: Is Ubisoft Backing Away from the DRM Abyss?

But the Dallas paper found six examples of grants to companies with backing from campaign contributors.

FORBES: Perry's New Jobs: How Many Are Pork For Contributors?

The Government's White Paper published last July, and for which there is backing from other parties, committed us to an 80% or 100% elected House of Lords.

BBC: In full: Constitution proposals