grammatically correct or not

[mahmoud1987]

hello dear
How are you
I have just read in "English vocabulary in use" pre-int. and int. by Stuart Redman, Cambridge University this paragraph :
page: 18
chapter: 7 prefixes
"I locked the door when I left, but I lost the key, so I couldn't it unlock it when I got back"

pls I want to know this statement it grammatically correct or not, and correct it.

thanks a lot

Mahmoud

[engee30]

hello dear
How are you
I have just read in "English vocabulary in use" pre-int. and int. by Stuart Redman, Cambridge University this paragraph :
page: 18
chapter: 7 prefixes
"I locked the door when I left, but I lost the key, so I couldn't (it typo???) unlock it when I got back"

pls I want to know this statement it grammatically correct or not, and correct it.

thanks a lot

Mahmoud

Take it for granted that the sentence taken from that book is correct (I reckon the first it following couldn't is just a typo).



I locked the door when I left (first you left home and then you locked the door), but I lost the key (you lost the key after leaving home), so I couldn't unlock it when I got back (the last event of the sequence of events - later on, getting back home, you were not able to unlock the door because you had lost the key earlier on).