Part C:
I,
1, It takes me an hour to clean the house ( take sb time to do smt=spend time doing smt)
2, The letter hasn't been stamped (by us).
3, He has not ( hasn't) called me for a long time.
4, He usually divides the duties in the family.
II,
1, Lan's father often lets her go camping with her friends in the mountain.
2, Every day, she does most of the housework.