The windows haven’t cleaned for a long time. They need ______.
I’m glad to see the rapid progress ______in science and technology in the past decade.
When we plan our vacation , mother often offers______suggestions.
Once there was ______time _____people walked without shoes.
________ came that another spaceship Shenzhou VII was successfully lifted off in our couvtry.
________ their son away to college, the couple got more room in the house.