He had left I could say hello to him. [ ]

The accident happened _______ a cold winter morning. [ ]

I am trying my best to learn English, but it doesn’t work well! —Don’t worry! Regard it _____ a big challenge! [ ]

It takes about 30 minutes _______ a bicycle from my home to school.

The man didn’t know _________ the thief broke into the house and stole all his valuable things