sneak a peek 抢先(偷)看；预览。
sneak peek = an opportunity to see something before it is officially available 预观（某物正式提供之前的观看机会）。
sneak a look/glance at sb/sth 很快地悄悄看...一眼。

【例句】
The company is offering a sneak peek at the new software.
该公司正在提供新软件的预用机会。

I noticed him sneak a look at what I was writing.
我注意到他悄悄地偷看了一眼我正在写的东西。