Perfect continuous infinitive digunakan untuk menyatakan tindakan yang sedang berlangsung tetapi sudah selesai sekarang, setelah kata kerja yang harus diikuti oleh infinitive. Perfect infinitive dibentuk dari::
to have been + present participle
Sama seperti present infinitive, ada situasi-situasi di mana bentuk zero dari perfect continuous infinitive harus digunakan, sehingga kata to dihilangkan. Hal ini dilakukan setelah penggunaan sebagian besar modal auxiliary dan tempat lain yang menggunakan zero infinitive.
Contoh
- The woman seemed to have been crying.
- He pretended to have been painting all day.
- I would have preferred to have been sleeping all afternoon.
- You must have been waiting for hours!
- They might have been talking before you came in.
- You should have been studying for your test.