Instead of just letting themselves drift off into dreamland, they kept on checking to see if they were still awake, and that quick mental check woke them up.

他们无法让自己沉入梦乡，反而不断自省是否尚未入眠，而正是这种时时短促的心理检查令他们难以入眠。

youdao

A slang term for an internal drift diameter gauge typically used to check casing or tubing joints before they are picked up and run into the wellbore.

在套管单根或油管单根被提起和下入井筒以前对其进行检查所用的内通径规的习用语。

youdao

After class VII, she started to slowly drift away but did keep a constant check on me.

下课后，她开始慢慢渐行渐远，但是却保持恒定的检查在我身上。

youdao