I couldn't catch the flight because ...
I failed the English exam because
I couldn't eat the steak because ...
I bought a new phone because ...
I couldn't find the restaurant because ...
I couldn't go swimming because ...
I didn't wake up on time because ...
I argued with my girlfriend because...
I hadn't studied
I had left my passport at home.
I had forgotten to set the alarm.
the chef hadn't cooked it enough.
I had lost the instructions
somebody had stolen it.
She had come home late.
I had left my swimsuit at home.