They suggest the number of cars should be limited to stop air pollution — ____, the idea is not practical

I didn’t understand ________led him to be late for three times every week.

People that lived in the mountains didn’t have wells in the past, so they had to ______ water from a stream far away.

My cousin went to Canada two years ago. He ____there for a few months and then went to America.

Jack, you look worried. What happened— I _____ forgot Mr. John’s project and I’m afraid he’ll be very angry.