It is __________ difficult work __________ nobody can do it well．

Look up(查阅) the following words in a dictionary , Which word can we find first ?

—______ a week do you walk your dog?   —Less than three times a week.

He is ______ the dark so he usually goes to sleep with the light ______.

In India,about_____ of people live in the country and some of them live a very poor life.