期望一夜之间学会一门外语是不切实际的。

It's ___unrealistic to expect to learn a foreign language overnight.

他认为自己能在一周内完成整个项目，这太不切实际了。

It's ___unrealistic to think he can finish the whole project in just one week.

这个广告对减肥效果的承诺太不切实际了。

The advertisement makes ___unrealistic promises about weight loss results.