Difficulties and hardships have ________ the best character of the young geologist.
To be well-informed, we should be _____ communication each other what happens to us.
What shall we use for power when all the oil in the world has _________?
Your uncle seems to be a good driver: _______, I wouldn’t dare to travel in his car.
Seeing the car trapped in the snow drift, the driver didn’t know ______ it.
________ English will help to communicate _____ people from different countries in the world.