—How long _____you ______ here? —About a week. Afterwards I will go to Beijing.

The little boy is dirty from head to foot because he______in the mud all morning.

His father, a famous university professor, who is said to have started his teaching career in Australia, _____ in Nanjing University for more than twenty years.

I ______ for Beijing in a few days. Do you know when the earliest plane ______?

 He left Wenzhou for Beijing last year, and we ________ him ever since.