_________ there are certainly times when giving up trying is the right thing to do, in most cases all needed is commitment and communication.

They felt ________ it was high tax and low income ________ contributed to the extreme misery of the working people at the bottom of the ladder.

It will be many years ______ the doctors and medical scientists can find _____ for cancer.

—Can you describe _____ it happened?　　　　—Yes, I was riding on my bike _____ a car knocked me down from behind.

It’s quite common in Britain to say “Thank you” to the drivers __       people get off the bus.