We do not know how astronauts can ________ when they spend months in space without the protection of the atmosphere.

As the road to the airport is under reconstruction, we’d better ________ early to avoid the traffic jam

Why is your bedroom so dirty— Sorry, Mum. It ___________. I felt very tired after playing soccer.

You used to be careful，________

By the speed of water flow, Tan made over 50 sounds from water.