—Have you ever _____ Mudanjiang to see the Jingbo Lake?—Yes, I have.
The houses in big cities are so expensive that I can’t __________ to buy one .
A smile costs _________, but gives so much. So we should learn to smile.
My mother often tells me ______ the teachers carefully
Look, Jim _______ football on the playground.
---Why did you laugh just now? ---Ted wanted to tell us _____ very funny story, but he forgot ______ ending himself.